71990388 has 18 divisors (see below), whose sum is σ = 181975794. Its totient is φ = 23996784.

The previous prime is 71990371. The next prime is 71990407. The reversal of 71990388 is 88309917.

It can be written as a sum of positive squares in only one way, i.e., 67272804 + 4717584 = 8202^2 + 2172^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is a congruent number.

It is an unprimeable number.

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 5 ways as a sum of consecutive naturals, for example, 999831 + ... + 999902.

Almost surely, 2^71990388 is an apocalyptic number.

It is an amenable number.

71990388 is an abundant number, since it is smaller than the sum of its proper divisors (109985406).

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

71990388 is a wasteful number, since it uses less digits than its factorization.

71990388 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1999743 (or 1999738 counting only the distinct ones).

The product of its (nonzero) digits is 108864, while the sum is 45.

The square root of 71990388 is about 8484.7149628022. The cubic root of 71990388 is about 415.9982510405.

The spelling of 71990388 in words is "seventy-one million, nine hundred ninety thousand, three hundred eighty-eight".