81296775 has 72 divisors (see below), whose sum is σ = 168989184. Its totient is φ = 36590400.

The previous prime is 81296741. The next prime is 81296777. The reversal of 81296775 is 57769218.

It is not a de Polignac number, because 81296775 - 2⁶ = 81296711 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 81296775.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81296777) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 111462 + ... + 112188.

It is an arithmetic number, because the mean of its divisors is an integer number (2347072).

Almost surely, 2^81296775 is an apocalyptic number.

81296775 is an abundant number, since it is smaller than the sum of its proper divisors (87692409).

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

81296775 is a wasteful number, since it uses less digits than its factorization.

81296775 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 821 (or 813 counting only the distinct ones).

The product of its digits is 211680, while the sum is 45.

The square root of 81296775 is about 9016.4724255110. The cubic root of 81296775 is about 433.2026512577.

The spelling of 81296775 in words is "eighty-one million, two hundred ninety-six thousand, seven hundred seventy-five".