81745072 has 10 divisors (see below), whose sum is σ = 158381108. Its totient is φ = 40872528.

The previous prime is 81745067. The next prime is 81745093. The reversal of 81745072 is 27054718.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2554518 + ... + 2554549.

Almost surely, 2^81745072 is an apocalyptic number.

It is an amenable number.

81745072 is a deficient number, since it is larger than the sum of its proper divisors (76636036).

81745072 is a wasteful number, since it uses less digits than its factorization.

81745072 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5109075 (or 5109069 counting only the distinct ones).

The product of its (nonzero) digits is 15680, while the sum is 34.

The square root of 81745072 is about 9041.2981368828. The cubic root of 81745072 is about 433.9974657769.

The spelling of 81745072 in words is "eighty-one million, seven hundred forty-five thousand, seventy-two".