81425609 has 8 divisors (see below), whose sum is σ = 82507680. Its totient is φ = 80349696.

The previous prime is 81425599. The next prime is 81425611. The reversal of 81425609 is 90652418.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 81425609 - 2⁸ = 81425353 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81425639) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 28937 + ... + 31625.

It is an arithmetic number, because the mean of its divisors is an integer number (10313460).

Almost surely, 2^81425609 is an apocalyptic number.

It is an amenable number.

81425609 is a deficient number, since it is larger than the sum of its proper divisors (1082071).

81425609 is a wasteful number, since it uses less digits than its factorization.

81425609 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3079.

The product of its (nonzero) digits is 17280, while the sum is 35.

The square root of 81425609 is about 9023.6139655905. The cubic root of 81425609 is about 433.4313678919.

The spelling of 81425609 in words is "eighty-one million, four hundred twenty-five thousand, six hundred nine".