71521990 has 16 divisors (see below), whose sum is σ = 128857680. Its totient is φ = 28582560.

The previous prime is 71521987. The next prime is 71521997. The reversal of 71521990 is 9912517.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (71521997) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11221 + ... + 16399.

It is an arithmetic number, because the mean of its divisors is an integer number (8053605).

Almost surely, 2^71521990 is an apocalyptic number.

71521990 is a deficient number, since it is larger than the sum of its proper divisors (57335690).

71521990 is a wasteful number, since it uses less digits than its factorization.

71521990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6567.

The product of its (nonzero) digits is 5670, while the sum is 34.

The square root of 71521990 is about 8457.0674586407. The cubic root of 71521990 is about 415.0940707056.

The spelling of 71521990 in words is "seventy-one million, five hundred twenty-one thousand, nine hundred ninety".