1640613638 has 4 divisors (see below), whose sum is σ = 2460920460. Its totient is φ = 820306818.

The previous prime is 1640613617. The next prime is 1640613643. The reversal of 1640613638 is 8363160461.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 8363160461 = 61057 ⋅136973.

It is a super-2 number, since 2×1640613638² = 5383226218383190088, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 410153408 + ... + 410153411.

It is an arithmetic number, because the mean of its divisors is an integer number (615230115).

Almost surely, 2^1640613638 is an apocalyptic number.

1640613638 is a deficient number, since it is larger than the sum of its proper divisors (820306822).

1640613638 is an equidigital number, since it uses as much as digits as its factorization.

1640613638 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 820306821.

The product of its (nonzero) digits is 62208, while the sum is 38.

The square root of 1640613638 is about 40504.4891092333. The cubic root of 1640613638 is about 1179.4207724093.

The spelling of 1640613638 in words is "one billion, six hundred forty million, six hundred thirteen thousand, six hundred thirty-eight".