81267755625 has 225 divisors, whose sum is σ = 177449347251. Its totient is φ = 36945720000.

The previous prime is 81267755603. The next prime is 81267755651. The reversal of 81267755625 is 52655776218.

The square root of 81267755625 is 285075.

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

81267755625 is a `hidden beast` number, since 8 + 1 + 2 + 6 + 7 + 7 + 5 + 5 + 625 = 666.

It can be written as a sum of positive squares in 7 ways, for example, as 78702130521 + 2565625104 = 280539^2 + 50652^2 .

It is a tau number, because it is divible by the number of its divisors (225).

It is not a de Polignac number, because 81267755625 - 2⁹ = 81267755113 is a prime.

Its product of digits (7056000) is a multiple of the sum of its prime divisors (196).

It is an unprimeable number.

It is a polite number, since it can be written in 224 ways as a sum of consecutive naturals, for example, 448993035 + ... + 448993215.

Almost surely, 2^81267755625 is an apocalyptic number.

81267755625 is the 285075-th square number.

81267755625 is the 142538-th centered octagonal number.

It is an amenable number.

81267755625 is an abundant number, since it is smaller than the sum of its proper divisors (96181591626).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81267755625 is an frugal number, since it uses more digits than its factorization.

81267755625 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 408 (or 196 counting only the distinct ones).

The product of its digits is 7056000, while the sum is 54.

The spelling of 81267755625 in words is "eighty-one billion, two hundred sixty-seven million, seven hundred fifty-five thousand, six hundred twenty-five".