1638090906 has 64 divisors (see below), whose sum is σ = 3421716480. Its totient is φ = 522434880.

The previous prime is 1638090901. The next prime is 1638090911. The reversal of 1638090906 is 6090908361.

It is an interprime number because it is at equal distance from previous prime (1638090901) and next prime (1638090911).

It is not an unprimeable number, because it can be changed into a prime (1638090901) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3419575 + ... + 3420053.

It is an arithmetic number, because the mean of its divisors is an integer number (53464320).

Almost surely, 2^1638090906 is an apocalyptic number.

1638090906 is an abundant number, since it is smaller than the sum of its proper divisors (1783625574).

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

1638090906 is a wasteful number, since it uses less digits than its factorization.

1638090906 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 779.

The product of its (nonzero) digits is 69984, while the sum is 42.

The square root of 1638090906 is about 40473.3357409542. The cubic root of 1638090906 is about 1178.8159400045.

The spelling of 1638090906 in words is "one billion, six hundred thirty-eight million, ninety thousand, nine hundred six".