81325761 has 24 divisors (see below), whose sum is σ = 119966496. Its totient is φ = 48599040.

The previous prime is 81325759. The next prime is 81325781. The reversal of 81325761 is 16752318.

It is not a de Polignac number, because 81325761 - 2¹ = 81325759 is a prime.

It is a super-2 number, since 2×81325761² = 13227758804458242, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is not an unprimeable number, because it can be changed into a prime (81325721) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 421281 + ... + 421473.

It is an arithmetic number, because the mean of its divisors is an integer number (4998604).

Almost surely, 2^81325761 is an apocalyptic number.

It is an amenable number.

81325761 is a deficient number, since it is larger than the sum of its proper divisors (38640735).

81325761 is a wasteful number, since it uses less digits than its factorization.

81325761 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 433 (or 320 counting only the distinct ones).

The product of its digits is 10080, while the sum is 33.

The square root of 81325761 is about 9018.0796736334. The cubic root of 81325761 is about 433.2541306265.

It can be divided in two parts, 813257 and 61, that added together give a palindrome (813318).

The spelling of 81325761 in words is "eighty-one million, three hundred twenty-five thousand, seven hundred sixty-one".