81413525 has 12 divisors (see below), whose sum is σ = 101281092. Its totient is φ = 64919040.

The previous prime is 81413419. The next prime is 81413539. The reversal of 81413525 is 52531418.

It can be written as a sum of positive squares in 6 ways, for example, as 23059204 + 58354321 = 4802^2 + 7639^2 .

It is not a de Polignac number, because 81413525 - 2¹⁰ = 81412501 is a prime.

It is a hoax number, since the sum of its digits (29) coincides with the sum of the digits of its distinct prime factors.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2789 + ... + 13061.

It is an arithmetic number, because the mean of its divisors is an integer number (8440091).

Almost surely, 2^81413525 is an apocalyptic number.

It is an amenable number.

81413525 is a deficient number, since it is larger than the sum of its proper divisors (19867567).

81413525 is a wasteful number, since it uses less digits than its factorization.

81413525 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10600 (or 10595 counting only the distinct ones).

The product of its digits is 4800, while the sum is 29.

The square root of 81413525 is about 9022.9443642306. The cubic root of 81413525 is about 433.4099256461.

The spelling of 81413525 in words is "eighty-one million, four hundred thirteen thousand, five hundred twenty-five".