71390728 has 8 divisors (see below), whose sum is σ = 133857630. Its totient is φ = 35695360.

The previous prime is 71390687. The next prime is 71390731. The reversal of 71390728 is 82709317.

It can be written as a sum of positive squares in only one way, i.e., 66292164 + 5098564 = 8142^2 + 2258^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is a hoax number, since the sum of its digits (37) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4461913 + ... + 4461928.

Almost surely, 2^71390728 is an apocalyptic number.

It is an amenable number.

71390728 is a deficient number, since it is larger than the sum of its proper divisors (62466902).

71390728 is a wasteful number, since it uses less digits than its factorization.

71390728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8923847 (or 8923843 counting only the distinct ones).

The product of its (nonzero) digits is 21168, while the sum is 37.

The square root of 71390728 is about 8449.3034032398. The cubic root of 71390728 is about 414.8399789495.

The spelling of 71390728 in words is "seventy-one million, three hundred ninety thousand, seven hundred twenty-eight".