81002905281 has 32 divisors (see below), whose sum is σ = 125249752320. Its totient is φ = 51642531072.

The previous prime is 81002905273. The next prime is 81002905309. The reversal of 81002905281 is 18250920018.

81002905281 is a `hidden beast` number, since 8 + 100 + 29 + 0 + 528 + 1 = 666.

It is not a de Polignac number, because 81002905281 - 2³ = 81002905273 is a prime.

It is a super-2 number, since 2×81002905281² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81002901281) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3439161 + ... + 3462633.

It is an arithmetic number, because the mean of its divisors is an integer number (3914054760).

Almost surely, 2^81002905281 is an apocalyptic number.

It is an amenable number.

81002905281 is a deficient number, since it is larger than the sum of its proper divisors (44246847039).

81002905281 is a wasteful number, since it uses less digits than its factorization.

81002905281 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29062 (or 29056 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 36.

The spelling of 81002905281 in words is "eighty-one billion, two million, nine hundred five thousand, two hundred eighty-one".