671671638 has 24 divisors (see below), whose sum is σ = 1587587976. Its totient is φ = 203536800.

The previous prime is 671671621. The next prime is 671671657. The reversal of 671671638 is 836176176.

671671638 is a `hidden beast` number, since 6 + 7 + 1 + 6 + 7 + 1 + 638 = 666.

It is a super-2 number, since 2×671671638² = 902285578587206088, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 671671593 and 671671602.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1695943 + ... + 1696338.

It is an arithmetic number, because the mean of its divisors is an integer number (66149499).

Almost surely, 2^671671638 is an apocalyptic number.

671671638 is an abundant number, since it is smaller than the sum of its proper divisors (915916338).

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

671671638 is a wasteful number, since it uses less digits than its factorization.

671671638 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3392300 (or 3392297 counting only the distinct ones).

The product of its digits is 254016, while the sum is 45.

The square root of 671671638 is about 25916.6286001864. The cubic root of 671671638 is about 875.7611392914.

The spelling of 671671638 in words is "six hundred seventy-one million, six hundred seventy-one thousand, six hundred thirty-eight".