1638381867 has 16 divisors (see below), whose sum is σ = 2246292480. Its totient is φ = 1061435232.

The previous prime is 1638381863. The next prime is 1638381881. The reversal of 1638381867 is 7681838361.

It is not a de Polignac number, because 1638381867 - 2² = 1638381863 is a prime.

It is a super-2 number, since 2×1638381867² = 5368590284228811378, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1638381863) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 86758 + ... + 103940.

It is an arithmetic number, because the mean of its divisors is an integer number (140393280).

Almost surely, 2^1638381867 is an apocalyptic number.

1638381867 is a deficient number, since it is larger than the sum of its proper divisors (607910613).

1638381867 is a wasteful number, since it uses less digits than its factorization.

1638381867 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18082.

The product of its digits is 1161216, while the sum is 51.

The square root of 1638381867 is about 40476.9300589855. The cubic root of 1638381867 is about 1178.8857304250.

The spelling of 1638381867 in words is "one billion, six hundred thirty-eight million, three hundred eighty-one thousand, eight hundred sixty-seven".