81171025 has 24 divisors (see below), whose sum is σ = 113117760. Its totient is φ = 57330240.

The previous prime is 81170987. The next prime is 81171031. The reversal of 81171025 is 52017118.

It is not a de Polignac number, because 81171025 - 2⁷ = 81170897 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (25).

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2046 + ... + 12904.

It is an arithmetic number, because the mean of its divisors is an integer number (4713240).

Almost surely, 2^81171025 is an apocalyptic number.

It is an amenable number.

81171025 is a deficient number, since it is larger than the sum of its proper divisors (31946735).

81171025 is a wasteful number, since it uses less digits than its factorization.

81171025 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10905 (or 10900 counting only the distinct ones).

The product of its (nonzero) digits is 560, while the sum is 25.

The square root of 81171025 is about 9009.4963788216. The cubic root of 81171025 is about 432.9791764437.

The spelling of 81171025 in words is "eighty-one million, one hundred seventy-one thousand, twenty-five".