1640639700 has 108 divisors (see below), whose sum is σ = 5877158560. Its totient is φ = 375001920.

The previous prime is 1640639687. The next prime is 1640639701. The reversal of 1640639700 is 79360461.

1640639700 is a `hidden beast` number, since 1 + 640 + 6 + 3 + 9 + 7 + 0 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1640639701) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 123910 + ... + 136509.

Almost surely, 2^1640639700 is an apocalyptic number.

1640639700 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1640639700 is an abundant number, since it is smaller than the sum of its proper divisors (4236518860).

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

1640639700 is a wasteful number, since it uses less digits than its factorization.

1640639700 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 260446 (or 260436 counting only the distinct ones).

The product of its (nonzero) digits is 27216, while the sum is 36.

The square root of 1640639700 is about 40504.8108253822. The cubic root of 1640639700 is about 1179.4270176135.

The spelling of 1640639700 in words is "one billion, six hundred forty million, six hundred thirty-nine thousand, seven hundred".