861081923025 has 135 divisors (see below), whose sum is σ = 1695763261731. Its totient is φ = 431873026560.

The previous prime is 861081922969. The next prime is 861081923027. The reversal of 861081923025 is 520329180168.

The square root of 861081923025 is 927945.

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

861081923025 is a `hidden beast` number, since 8 + 610 + 8 + 1 + 9 + 2 + 3 + 0 + 25 = 666.

It can be written as a sum of positive squares in 13 ways, for example, as 755965908369 + 105116014656 = 869463^2 + 324216^2 .

It is a tau number, because it is divible by the number of its divisors (135).

It is not a de Polignac number, because 861081923025 - 2¹¹ = 861081920977 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is not an unprimeable number, because it can be changed into a prime (861081923027) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 134 ways as a sum of consecutive naturals, for example, 709877319 + ... + 709878531.

Almost surely, 2^861081923025 is an apocalyptic number.

861081923025 is a gapful number since it is divisible by the number (85) formed by its first and last digit.

861081923025 is the 927945-th square number.

861081923025 is the 463973-rd centered octagonal number.

It is an amenable number.

861081923025 is a deficient number, since it is larger than the sum of its proper divisors (834681338706).

861081923025 is an equidigital number, since it uses as much as digits as its factorization.

861081923025 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2482 (or 1238 counting only the distinct ones).

The product of its (nonzero) digits is 207360, while the sum is 45.

The spelling of 861081923025 in words is "eight hundred sixty-one billion, eighty-one million, nine hundred twenty-three thousand, twenty-five".