1021620256 has 48 divisors (see below), whose sum is σ = 2104014528. Its totient is φ = 487379200.

The previous prime is 1021620251. The next prime is 1021620269. The reversal of 1021620256 is 6520261201.

It is a self number, because there is not a number n which added to its sum of digits gives 1021620256.

It is not an unprimeable number, because it can be changed into a prime (1021620251) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 337791 + ... + 340801.

It is an arithmetic number, because the mean of its divisors is an integer number (43833636).

Almost surely, 2^1021620256 is an apocalyptic number.

1021620256 is a gapful number since it is divisible by the number (16) 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 1021620256, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1052007264).

1021620256 is an abundant number, since it is smaller than the sum of its proper divisors (1082394272).

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

1021620256 is a wasteful number, since it uses less digits than its factorization.

1021620256 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3505 (or 3497 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 25.

The square root of 1021620256 is about 31962.7948715378. The cubic root of 1021620256 is about 1007.1554297060.

Adding to 1021620256 its reverse (6520261201), we get a palindrome (7541881457).

The spelling of 1021620256 in words is "one billion, twenty-one million, six hundred twenty thousand, two hundred fifty-six".