1638404536 has 16 divisors (see below), whose sum is σ = 3072480840. Its totient is φ = 819076320.

The previous prime is 1638404531. The next prime is 1638404543. The reversal of 1638404536 is 6354048361.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1638404531) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 62295 + ... + 84601.

Almost surely, 2^1638404536 is an apocalyptic number.

It is an amenable number.

1638404536 is a deficient number, since it is larger than the sum of its proper divisors (1434076304).

1638404536 is a wasteful number, since it uses less digits than its factorization.

1638404536 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31494 (or 31490 counting only the distinct ones).

The product of its (nonzero) digits is 207360, while the sum is 40.

The square root of 1638404536 is about 40477.2100817238. The cubic root of 1638404536 is about 1178.8911675045.

The spelling of 1638404536 in words is "one billion, six hundred thirty-eight million, four hundred four thousand, five hundred thirty-six".