1664432256 has 32 divisors (see below), whose sum is σ = 4421149200. Its totient is φ = 554810624.

The previous prime is 1664432251. The next prime is 1664432279. The reversal of 1664432256 is 6522344661.

It is a tau number, because it is divible by the number of its divisors (32).

It is not an unprimeable number, because it can be changed into a prime (1664432251) 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, 2166846 + ... + 2167613.

Almost surely, 2^1664432256 is an apocalyptic number.

1664432256 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

1664432256 is an abundant number, since it is smaller than the sum of its proper divisors (2756716944).

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

1664432256 is an equidigital number, since it uses as much as digits as its factorization.

1664432256 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4334476 (or 4334464 counting only the distinct ones).

The product of its digits is 207360, while the sum is 39.

The square root of 1664432256 is about 40797.4540382117. The cubic root of 1664432256 is about 1185.1010271893.

The spelling of 1664432256 in words is "one billion, six hundred sixty-four million, four hundred thirty-two thousand, two hundred fifty-six".