1021566220 has 12 divisors (see below), whose sum is σ = 2145289104. Its totient is φ = 408626480.

The previous prime is 1021566199. The next prime is 1021566223. The reversal of 1021566220 is 226651201.

It is not an unprimeable number, because it can be changed into a prime (1021566223) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 25539136 + ... + 25539175.

It is an arithmetic number, because the mean of its divisors is an integer number (178774092).

Almost surely, 2^1021566220 is an apocalyptic number.

1021566220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1021566220 is an abundant number, since it is smaller than the sum of its proper divisors (1123722884).

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

1021566220 is a wasteful number, since it uses less digits than its factorization.

1021566220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 51078320 (or 51078318 counting only the distinct ones).

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

The square root of 1021566220 is about 31961.9495650688. The cubic root of 1021566220 is about 1007.1376724196.

The spelling of 1021566220 in words is "one billion, twenty-one million, five hundred sixty-six thousand, two hundred twenty".