81261415285 has 8 divisors (see below), whose sum is σ = 97658596440. Its totient is φ = 64912533504.

The previous prime is 81261415271. The next prime is 81261415309. The reversal of 81261415285 is 58251416218.

It can be written as a sum of positive squares in 4 ways, for example, as 21594609 + 81239820676 = 4647^2 + 285026^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 81261415285 - 2³⁵ = 46901676917 is a prime.

It is a super-2 number, since 2×81261415285² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12071140 + ... + 12077869.

It is an arithmetic number, because the mean of its divisors is an integer number (12207324555).

Almost surely, 2^81261415285 is an apocalyptic number.

It is an amenable number.

81261415285 is a deficient number, since it is larger than the sum of its proper divisors (16397181155).

81261415285 is a wasteful number, since it uses less digits than its factorization.

81261415285 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24149687.

The product of its digits is 153600, while the sum is 43.

The spelling of 81261415285 in words is "eighty-one billion, two hundred sixty-one million, four hundred fifteen thousand, two hundred eighty-five".