81952791 has 4 divisors (see below), whose sum is σ = 109270392. Its totient is φ = 54635192.

The previous prime is 81952781. The next prime is 81952799. The reversal of 81952791 is 19725918.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 81952791 - 2¹⁵ = 81920023 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81952799) 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, 13658796 + ... + 13658801.

It is an arithmetic number, because the mean of its divisors is an integer number (27317598).

Almost surely, 2^81952791 is an apocalyptic number.

81952791 is a deficient number, since it is larger than the sum of its proper divisors (27317601).

81952791 is a wasteful number, since it uses less digits than its factorization.

81952791 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27317600.

The product of its digits is 45360, while the sum is 42.

The square root of 81952791 is about 9052.7780818929. The cubic root of 81952791 is about 434.3647591464.

The spelling of 81952791 in words is "eighty-one million, nine hundred fifty-two thousand, seven hundred ninety-one".