71643690 has 48 divisors (see below), whose sum is σ = 193179168. Its totient is φ = 19104336.

The previous prime is 71643673. The next prime is 71643701. The reversal of 71643690 is 9634617.

71643690 is a `hidden beast` number, since 7 + 1 + 643 + 6 + 9 + 0 = 666.

It is a super-2 number, since 2×71643690² = 10265636633632200, which contains 22 as substring.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 12312 + ... + 17171.

It is an arithmetic number, because the mean of its divisors is an integer number (4024566).

Almost surely, 2^71643690 is an apocalyptic number.

71643690 is an abundant number, since it is smaller than the sum of its proper divisors (121535478).

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

71643690 is a wasteful number, since it uses less digits than its factorization.

71643690 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29505 (or 29493 counting only the distinct ones).

The product of its (nonzero) digits is 27216, while the sum is 36.

The square root of 71643690 is about 8464.2595659632. The cubic root of 71643690 is about 415.3293751328.

The spelling of 71643690 in words is "seventy-one million, six hundred forty-three thousand, six hundred ninety".