1638932660 has 12 divisors (see below), whose sum is σ = 3441758628. Its totient is φ = 655573056.

The previous prime is 1638932639. The next prime is 1638932681. The reversal of 1638932660 is 662398361.

It is an interprime number because it is at equal distance from previous prime (1638932639) and next prime (1638932681).

It can be written as a sum of positive squares in 2 ways, for example, as 705752356 + 933180304 = 26566^2 + 30548^2 .

It is a super-2 number, since 2×1638932660² = 5372200528029351200, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 40973297 + ... + 40973336.

It is an arithmetic number, because the mean of its divisors is an integer number (286813219).

Almost surely, 2^1638932660 is an apocalyptic number.

1638932660 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1638932660 is an abundant number, since it is smaller than the sum of its proper divisors (1802825968).

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

1638932660 is a wasteful number, since it uses less digits than its factorization.

1638932660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81946642 (or 81946640 counting only the distinct ones).

The product of its (nonzero) digits is 279936, while the sum is 44.

The square root of 1638932660 is about 40483.7332764655. The cubic root of 1638932660 is about 1179.0178219867.

The spelling of 1638932660 in words is "one billion, six hundred thirty-eight million, nine hundred thirty-two thousand, six hundred sixty".