81656277 has 4 divisors (see below), whose sum is σ = 108875040. Its totient is φ = 54437516.

The previous prime is 81656273. The next prime is 81656291. The reversal of 81656277 is 77265618.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 81656277 - 2² = 81656273 is a prime.

It is a super-3 number, since 3×81656277³ (a number of 25 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81656273) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13609377 + ... + 13609382.

It is an arithmetic number, because the mean of its divisors is an integer number (27218760).

Almost surely, 2^81656277 is an apocalyptic number.

It is an amenable number.

81656277 is a deficient number, since it is larger than the sum of its proper divisors (27218763).

81656277 is a wasteful number, since it uses less digits than its factorization.

81656277 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27218762.

The product of its digits is 141120, while the sum is 42.

The square root of 81656277 is about 9036.3862799241. The cubic root of 81656277 is about 433.8402666296.

The spelling of 81656277 in words is "eighty-one million, six hundred fifty-six thousand, two hundred seventy-seven".