1640987964 has 144 divisors (see below), whose sum is σ = 5344684800. Its totient is φ = 426206880.

The previous prime is 1640987927. The next prime is 1640988001. The reversal of 1640987964 is 4697890461.

It is an interprime number because it is at equal distance from previous prime (1640987927) and next prime (1640988001).

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a self number, because there is not a number n which added to its sum of digits gives 1640987964.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 82507 + ... + 100445.

Almost surely, 2^1640987964 is an apocalyptic number.

1640987964 is a gapful number since it is divisible by the number (14) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1640987964, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2672342400).

1640987964 is an abundant number, since it is smaller than the sum of its proper divisors (3703696836).

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

1640987964 is a wasteful number, since it uses less digits than its factorization.

1640987964 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17981 (or 17962 counting only the distinct ones).

The product of its (nonzero) digits is 2612736, while the sum is 54.

The square root of 1640987964 is about 40509.1096421533. The cubic root of 1640987964 is about 1179.5104653301.

The spelling of 1640987964 in words is "one billion, six hundred forty million, nine hundred eighty-seven thousand, nine hundred sixty-four".