81387425 has 12 divisors (see below), whose sum is σ = 115337856. Its totient is φ = 55808400.

The previous prime is 81387403. The next prime is 81387437. The reversal of 81387425 is 52478318.

It is not a de Polignac number, because 81387425 - 2¹⁸ = 81125281 is a prime.

It is a Duffinian 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, 232361 + ... + 232710.

It is an arithmetic number, because the mean of its divisors is an integer number (9611488).

Almost surely, 2^81387425 is an apocalyptic number.

It is an amenable number.

81387425 is a deficient number, since it is larger than the sum of its proper divisors (33950431).

81387425 is a wasteful number, since it uses less digits than its factorization.

81387425 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 465088 (or 465083 counting only the distinct ones).

The product of its digits is 53760, while the sum is 38.

The square root of 81387425 is about 9021.4979354872. The cubic root of 81387425 is about 433.3636057089.

The spelling of 81387425 in words is "eighty-one million, three hundred eighty-seven thousand, four hundred twenty-five".