81662425 has 24 divisors (see below), whose sum is σ = 110617920. Its totient is φ = 59438400.

The previous prime is 81662423. The next prime is 81662429. The reversal of 81662425 is 52426618.

It is not a de Polignac number, because 81662425 - 2¹ = 81662423 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81662423) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 21306 + ... + 24844.

It is an arithmetic number, because the mean of its divisors is an integer number (4609080).

Almost surely, 2^81662425 is an apocalyptic number.

It is an amenable number.

81662425 is a deficient number, since it is larger than the sum of its proper divisors (28955495).

81662425 is a wasteful number, since it uses less digits than its factorization.

81662425 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3633 (or 3628 counting only the distinct ones).

The product of its digits is 23040, while the sum is 34.

The square root of 81662425 is about 9036.7264537553. The cubic root of 81662425 is about 433.8511544761.

The spelling of 81662425 in words is "eighty-one million, six hundred sixty-two thousand, four hundred twenty-five".