81584525 has 24 divisors (see below), whose sum is σ = 110909568. Its totient is φ = 59040000.

The previous prime is 81584509. The next prime is 81584539. The reversal of 81584525 is 52548518.

It is not a de Polignac number, because 81584525 - 2⁴ = 81584509 is a prime.

It is a congruent number.

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, 65660 + ... + 66890.

It is an arithmetic number, because the mean of its divisors is an integer number (4621232).

Almost surely, 2^81584525 is an apocalyptic number.

It is an amenable number.

81584525 is a deficient number, since it is larger than the sum of its proper divisors (29325043).

81584525 is a wasteful number, since it uses less digits than its factorization.

81584525 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1493 (or 1488 counting only the distinct ones).

The product of its digits is 64000, while the sum is 38.

The square root of 81584525 is about 9032.4152362477. The cubic root of 81584525 is about 433.7131564627.

The spelling of 81584525 in words is "eighty-one million, five hundred eighty-four thousand, five hundred twenty-five".