81426861 has 24 divisors (see below), whose sum is σ = 121375800. Its totient is φ = 52569600.

The previous prime is 81426859. The next prime is 81426869. The reversal of 81426861 is 16862418.

It can be written as a sum of positive squares in 4 ways, for example, as 1664100 + 79762761 = 1290^2 + 8931^2 .

It is not a de Polignac number, because 81426861 - 2¹ = 81426859 is a prime.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81426869) 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, 54241 + ... + 55721.

It is an arithmetic number, because the mean of its divisors is an integer number (5057325).

Almost surely, 2^81426861 is an apocalyptic number.

It is an amenable number.

81426861 is a deficient number, since it is larger than the sum of its proper divisors (39948939).

81426861 is a wasteful number, since it uses less digits than its factorization.

81426861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1677 (or 1674 counting only the distinct ones).

The product of its digits is 18432, while the sum is 36.

The square root of 81426861 is about 9023.6833388589. The cubic root of 81426861 is about 433.4335893605.

The spelling of 81426861 in words is "eighty-one million, four hundred twenty-six thousand, eight hundred sixty-one".