1638843634 has 24 divisors (see below), whose sum is σ = 2514859200. Its totient is φ = 800970768.

The previous prime is 1638843607. The next prime is 1638843637. The reversal of 1638843634 is 4363488361.

It is not an unprimeable number, because it can be changed into a prime (1638843637) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2735667 + ... + 2736265.

It is an arithmetic number, because the mean of its divisors is an integer number (104785800).

Almost surely, 2^1638843634 is an apocalyptic number.

1638843634 is a deficient number, since it is larger than the sum of its proper divisors (876015566).

1638843634 is an equidigital number, since it uses as much as digits as its factorization.

1638843634 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1194 (or 1141 counting only the distinct ones).

The product of its digits is 995328, while the sum is 46.

The square root of 1638843634 is about 40482.6337334912. The cubic root of 1638843634 is about 1178.9964737146.

The spelling of 1638843634 in words is "one billion, six hundred thirty-eight million, eight hundred forty-three thousand, six hundred thirty-four".