81392225 has 12 divisors (see below), whose sum is σ = 101872944. Its totient is φ = 64503120.

The previous prime is 81392221. The next prime is 81392251. The reversal of 81392225 is 52229318.

It is a happy number.

It is not a de Polignac number, because 81392225 - 2² = 81392221 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81392191 and 81392200.

It is not an unprimeable number, because it can be changed into a prime (81392221) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 12539 + ... + 17888.

It is an arithmetic number, because the mean of its divisors is an integer number (8489412).

Almost surely, 2^81392225 is an apocalyptic number.

It is an amenable number.

81392225 is a deficient number, since it is larger than the sum of its proper divisors (20480719).

81392225 is a wasteful number, since it uses less digits than its factorization.

81392225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30544 (or 30539 counting only the distinct ones).

The product of its digits is 8640, while the sum is 32.

The square root of 81392225 is about 9021.7639627736. The cubic root of 81392225 is about 433.3721250611.

The spelling of 81392225 in words is "eighty-one million, three hundred ninety-two thousand, two hundred twenty-five".