1644649956 has 36 divisors (see below), whose sum is σ = 4376117200. Its totient is φ = 519362928.

The previous prime is 1644649907. The next prime is 1644649967. The reversal of 1644649956 is 6599464461.

1644649956 is a `hidden beast` number, since 1 + 64 + 46 + 499 + 56 = 666.

1644649956 is nontrivially palindromic in base 7.

It is a tau number, because it is divible by the number of its divisors (36).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1201546 + ... + 1202913.

Almost surely, 2^1644649956 is an apocalyptic number.

It is an amenable number.

1644649956 is an abundant number, since it is smaller than the sum of its proper divisors (2731467244).

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

1644649956 is a wasteful number, since it uses less digits than its factorization.

1644649956 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2404488 (or 2404483 counting only the distinct ones).

The product of its digits is 5598720, while the sum is 54.

The square root of 1644649956 is about 40554.2840646953. The cubic root of 1644649956 is about 1180.3872031990.

The spelling of 1644649956 in words is "one billion, six hundred forty-four million, six hundred forty-nine thousand, nine hundred fifty-six".