1640691216 has 60 divisors (see below), whose sum is σ = 4861761372. Its totient is φ = 514725888.

The previous prime is 1640691209. The next prime is 1640691251. The reversal of 1640691216 is 6121960461.

1640691216 is a `hidden beast` number, since 1 + 640 + 6 + 9 + 1 + 2 + 1 + 6 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 571401216 + 1069290000 = 23904^2 + 32700^2 .

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (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, 332661 + ... + 337556.

Almost surely, 2^1640691216 is an apocalyptic number.

1640691216 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

1640691216 is an abundant number, since it is smaller than the sum of its proper divisors (3221070156).

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

1640691216 is a wasteful number, since it uses less digits than its factorization.

1640691216 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 670248 (or 670239 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 36.

The square root of 1640691216 is about 40505.4467448515. The cubic root of 1640691216 is about 1179.4393621330.

The spelling of 1640691216 in words is "one billion, six hundred forty million, six hundred ninety-one thousand, two hundred sixteen".