81408825 has 72 divisors (see below), whose sum is σ = 155719200. Its totient is φ = 40538880.

The previous prime is 81408809. The next prime is 81408851. The reversal of 81408825 is 52880418.

It is not a de Polignac number, because 81408825 - 2⁴ = 81408809 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81408825.

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 585606 + ... + 585744.

Almost surely, 2^81408825 is an apocalyptic number.

It is an amenable number.

81408825 is a deficient number, since it is larger than the sum of its proper divisors (74310375).

81408825 is a wasteful number, since it uses less digits than its factorization.

81408825 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 311 (or 303 counting only the distinct ones).

The product of its (nonzero) digits is 20480, while the sum is 36.

The square root of 81408825 is about 9022.6839133375. The cubic root of 81408825 is about 433.4015852389.

The spelling of 81408825 in words is "eighty-one million, four hundred eight thousand, eight hundred twenty-five".