1220021660 has 192 divisors, whose sum is σ = 3328625664. Its totient is φ = 368332800.

The previous prime is 1220021659. The next prime is 1220021717. The reversal of 1220021660 is 661200221.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (20).

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 63 ways as a sum of consecutive naturals, for example, 1117715 + ... + 1118805.

It is an arithmetic number, because the mean of its divisors is an integer number (17336592).

Almost surely, 2^1220021660 is an apocalyptic number.

1220021660 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 1220021660, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1664312832).

1220021660 is an abundant number, since it is smaller than the sum of its proper divisors (2108604004).

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

1220021660 is a wasteful number, since it uses less digits than its factorization.

1220021660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1164 (or 1162 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 20.

The square root of 1220021660 is about 34928.8084537678. The cubic root of 1220021660 is about 1068.5360537054.

Adding to 1220021660 its reverse (661200221), we get a palindrome (1881221881).

The spelling of 1220021660 in words is "one billion, two hundred twenty million, twenty-one thousand, six hundred sixty".