81023831825 has 6 divisors (see below), whose sum is σ = 100469551494. Its totient is φ = 64819065440.

The previous prime is 81023831821. The next prime is 81023831839. The reversal of 81023831825 is 52813832018.

It can be written as a sum of positive squares in 3 ways, for example, as 13010449 + 81010821376 = 3607^2 + 284624^2 .

It is not a de Polignac number, because 81023831825 - 2² = 81023831821 is a prime.

It is a super-2 number, since 2×81023831825² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81023831821) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1620476612 + ... + 1620476661.

It is an arithmetic number, because the mean of its divisors is an integer number (16744925249).

Almost surely, 2^81023831825 is an apocalyptic number.

It is an amenable number.

81023831825 is a deficient number, since it is larger than the sum of its proper divisors (19445719669).

81023831825 is a wasteful number, since it uses less digits than its factorization.

81023831825 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3240953283 (or 3240953278 counting only the distinct ones).

The product of its (nonzero) digits is 92160, while the sum is 41.

The spelling of 81023831825 in words is "eighty-one billion, twenty-three million, eight hundred thirty-one thousand, eight hundred twenty-five".