81275772 has 12 divisors (see below), whose sum is σ = 189643496. Its totient is φ = 27091920.

The previous prime is 81275743. The next prime is 81275801. The reversal of 81275772 is 27757218.

It is an interprime number because it is at equal distance from previous prime (81275743) and next prime (81275801).

It is a tau number, because it is divible by the number of its divisors (12).

It is a super-2 number, since 2×81275772² = 13211502228391968, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 81275772.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3386479 + ... + 3386502.

Almost surely, 2^81275772 is an apocalyptic number.

It is an amenable number.

81275772 is an abundant number, since it is smaller than the sum of its proper divisors (108367724).

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

81275772 is a wasteful number, since it uses less digits than its factorization.

81275772 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6772988 (or 6772986 counting only the distinct ones).

The product of its digits is 54880, while the sum is 39.

The square root of 81275772 is about 9015.3076486607. The cubic root of 81275772 is about 433.1653421150.

The spelling of 81275772 in words is "eighty-one million, two hundred seventy-five thousand, seven hundred seventy-two".