81307671025 has 27 divisors (see below), whose sum is σ = 117296564619. Its totient is φ = 55746988080.

The previous prime is 81307671017. The next prime is 81307671073. The reversal of 81307671025 is 52017670318.

The square root of 81307671025 is 285145.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 29270761569 + 52036909456 = 171087^2 + 228116^2 .

It is not a de Polignac number, because 81307671025 - 2³ = 81307671017 is a prime.

It is a super-2 number, since 2×81307671025² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is an unprimeable number.

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 26 ways as a sum of consecutive naturals, for example, 9976002 + ... + 9984148.

Almost surely, 2^81307671025 is an apocalyptic number.

81307671025 is the 285145-th square number.

81307671025 is the 142573-rd centered octagonal number.

It is an amenable number.

81307671025 is a deficient number, since it is larger than the sum of its proper divisors (35988893594).

81307671025 is an frugal number, since it uses more digits than its factorization.

81307671025 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16318 (or 8159 counting only the distinct ones).

The product of its (nonzero) digits is 70560, while the sum is 40.

The spelling of 81307671025 in words is "eighty-one billion, three hundred seven million, six hundred seventy-one thousand, twenty-five".