1021665056 has 24 divisors (see below), whose sum is σ = 2012214960. Its totient is φ = 510626368.

The previous prime is 1021665023. The next prime is 1021665059. The reversal of 1021665056 is 6505661201.

It is a Harshad number since it is a multiple of its sum of digits (32).

It is not an unprimeable number, because it can be changed into a prime (1021665059) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 102335 + ... + 111873.

It is an arithmetic number, because the mean of its divisors is an integer number (83842290).

Almost surely, 2^1021665056 is an apocalyptic number.

1021665056 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

1021665056 is a deficient number, since it is larger than the sum of its proper divisors (990549904).

1021665056 is an equidigital number, since it uses as much as digits as its factorization.

1021665056 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12896 (or 12888 counting only the distinct ones).

The product of its (nonzero) digits is 10800, while the sum is 32.

The square root of 1021665056 is about 31963.4956786644. The cubic root of 1021665056 is about 1007.1701513874.

The spelling of 1021665056 in words is "one billion, twenty-one million, six hundred sixty-five thousand, fifty-six".