81577117 has 4 divisors (see below), whose sum is σ = 82959840. Its totient is φ = 80194396.

The previous prime is 81577103. The next prime is 81577129. The reversal of 81577117 is 71177518.

It is a happy number.

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 81577117 - 2¹⁵ = 81544349 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81577157) 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, 691273 + ... + 691390.

It is an arithmetic number, because the mean of its divisors is an integer number (20739960).

Almost surely, 2^81577117 is an apocalyptic number.

It is an amenable number.

81577117 is a deficient number, since it is larger than the sum of its proper divisors (1382723).

81577117 is a wasteful number, since it uses less digits than its factorization.

81577117 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1382722.

The product of its digits is 13720, while the sum is 37.

The square root of 81577117 is about 9032.0051483599. The cubic root of 81577117 is about 433.7000287921.

The spelling of 81577117 in words is "eighty-one million, five hundred seventy-seven thousand, one hundred seventeen".