81288525 has 12 divisors (see below), whose sum is σ = 134397152. Its totient is φ = 43353840.

The previous prime is 81288511. The next prime is 81288547. The reversal of 81288525 is 52588218.

It is not a de Polignac number, because 81288525 - 2⁶ = 81288461 is a prime.

It is a hoax number, since the sum of its digits (39) 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 polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 541849 + ... + 541998.

Almost surely, 2^81288525 is an apocalyptic number.

It is an amenable number.

81288525 is a deficient number, since it is larger than the sum of its proper divisors (53108627).

81288525 is a wasteful number, since it uses less digits than its factorization.

81288525 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1083860 (or 1083855 counting only the distinct ones).

The product of its digits is 51200, while the sum is 39.

The square root of 81288525 is about 9016.0149179113. The cubic root of 81288525 is about 433.1879969545.

It can be divided in two parts, 8128 and 8525, that added together give a triangular number (16653 = T₁₈₂).

The spelling of 81288525 in words is "eighty-one million, two hundred eighty-eight thousand, five hundred twenty-five".