1565213220 has 120 divisors (see below), whose sum is σ = 5043031224. Its totient is φ = 406093824.

The previous prime is 1565213191. The next prime is 1565213249. The reversal of 1565213220 is 223125651.

It is a happy number.

1565213220 is a `hidden beast` number, since 1 + 5 + 652 + 1 + 3 + 2 + 2 + 0 = 666.

It is an interprime number because it is at equal distance from previous prime (1565213191) and next prime (1565213249).

It can be written as a sum of positive squares in 4 ways, for example, as 520113636 + 1045099584 = 22806^2 + 32328^2 .

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 46884 + ... + 72996.

Almost surely, 2^1565213220 is an apocalyptic number.

1565213220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1565213220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2521515612).

1565213220 is an abundant number, since it is smaller than the sum of its proper divisors (3477818004).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1565213220 is a wasteful number, since it uses less digits than its factorization.

1565213220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26171 (or 26160 counting only the distinct ones).

The product of its (nonzero) digits is 3600, while the sum is 27.

The square root of 1565213220 is about 39562.7756862432. The cubic root of 1565213220 is about 1161.0684814282.

Adding to 1565213220 its reverse (223125651), we get a palindrome (1788338871).

The spelling of 1565213220 in words is "one billion, five hundred sixty-five million, two hundred thirteen thousand, two hundred twenty".