1640991312 has 50 divisors (see below), whose sum is σ = 4749508698. Its totient is φ = 546996672.

The previous prime is 1640991227. The next prime is 1640991337. The reversal of 1640991312 is 2131990461.

It is a happy number.

1640991312 is a `hidden beast` number, since 1 + 640 + 9 + 9 + 1 + 3 + 1 + 2 = 666.

It can be written as a sum of positive squares in only one way, i.e., 1298593296 + 342398016 = 36036^2 + 18504^2 .

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 631803 + ... + 634394.

Almost surely, 2^1640991312 is an apocalyptic number.

1640991312 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

1640991312 is an abundant number, since it is smaller than the sum of its proper divisors (3108517386).

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

1640991312 is a wasteful number, since it uses less digits than its factorization.

1640991312 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1266217 (or 1266202 counting only the distinct ones).

The product of its (nonzero) digits is 11664, while the sum is 36.

The square root of 1640991312 is about 40509.1509661706. The cubic root of 1640991312 is about 1179.5112674888.

The spelling of 1640991312 in words is "one billion, six hundred forty million, nine hundred ninety-one thousand, three hundred twelve".