81925542920529 has 405 divisors, whose sum is σ = 161282559602241. Its totient is φ = 41291183324160.

The previous prime is 81925542920527. The next prime is 81925542920587. The reversal of 81925542920529 is 92502924552918.

The square root of 81925542920529 is 9051273.

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

81925542920529 is a `hidden beast` number, since 8 + 1 + 9 + 2 + 554 + 2 + 9 + 20 + 52 + 9 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 10210728148929 + 71714814771600 = 3195423^2 + 8468460^2 .

It is not a de Polignac number, because 81925542920529 - 2¹ = 81925542920527 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is not an unprimeable number, because it can be changed into a prime (81925542920527) by changing a digit.

It is a polite number, since it can be written in 404 ways as a sum of consecutive naturals, for example, 232083690817 + ... + 232083691169.

Almost surely, 2^{81925542920529} is an apocalyptic number.

81925542920529 is the 9051273-rd square number.

81925542920529 is the 4525637-th centered octagonal number.

It is an amenable number.

81925542920529 is a deficient number, since it is larger than the sum of its proper divisors (79357016681712).

81925542920529 is an equidigital number, since it uses as much as digits as its factorization.

81925542920529 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 828 (or 411 counting only the distinct ones).

The product of its (nonzero) digits is 46656000, while the sum is 63.

The spelling of 81925542920529 in words is "eighty-one trillion, nine hundred twenty-five billion, five hundred forty-two million, nine hundred twenty thousand, five hundred twenty-nine".