1645440656 has 40 divisors (see below), whose sum is σ = 3226192320. Its totient is φ = 812912256.

The previous prime is 1645440619. The next prime is 1645440697. The reversal of 1645440656 is 6560445461.

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 7 ways as a sum of consecutive naturals, for example, 1019306 + ... + 1020918.

It is an arithmetic number, because the mean of its divisors is an integer number (80654808).

Almost surely, 2^1645440656 is an apocalyptic number.

1645440656 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

1645440656 is a deficient number, since it is larger than the sum of its proper divisors (1580751664).

1645440656 is a wasteful number, since it uses less digits than its factorization.

1645440656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2343 (or 2337 counting only the distinct ones).

The product of its (nonzero) digits is 345600, while the sum is 41.

The square root of 1645440656 is about 40564.0315550612. The cubic root of 1645440656 is about 1180.5763382031.

The spelling of 1645440656 in words is "one billion, six hundred forty-five million, four hundred forty thousand, six hundred fifty-six".