81877291 has 4 divisors (see below), whose sum is σ = 82109592. Its totient is φ = 81644992.

The previous prime is 81877249. The next prime is 81877297. The reversal of 81877291 is 19277818.

It is a happy number.

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 81877291 - 2¹¹ = 81875243 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81877297) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 115621 + ... + 116326.

It is an arithmetic number, because the mean of its divisors is an integer number (20527398).

Almost surely, 2^81877291 is an apocalyptic number.

81877291 is a deficient number, since it is larger than the sum of its proper divisors (232301).

81877291 is a wasteful number, since it uses less digits than its factorization.

81877291 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 232300.

The product of its digits is 56448, while the sum is 43.

The square root of 81877291 is about 9048.6071303820. The cubic root of 81877291 is about 434.2313302343.

The spelling of 81877291 in words is "eighty-one million, eight hundred seventy-seven thousand, two hundred ninety-one".