1640938640 has 40 divisors (see below), whose sum is σ = 4162019328. Its totient is φ = 596704640.

The previous prime is 1640938631. The next prime is 1640938643. The reversal of 1640938640 is 468390461.

It is a tau number, because it is divible by the number of its divisors (40).

It is not an unprimeable number, because it can be changed into a prime (1640938643) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 931472 + ... + 933231.

Almost surely, 2^1640938640 is an apocalyptic number.

1640938640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1640938640 is an abundant number, since it is smaller than the sum of its proper divisors (2521080688).

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

1640938640 is a wasteful number, since it uses less digits than its factorization.

1640938640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1864727 (or 1864721 counting only the distinct ones).

The product of its (nonzero) digits is 124416, while the sum is 41.

The square root of 1640938640 is about 40508.5008362442. The cubic root of 1640938640 is about 1179.4986474987.

The spelling of 1640938640 in words is "one billion, six hundred forty million, nine hundred thirty-eight thousand, six hundred forty".