81357425 has 12 divisors (see below), whose sum is σ = 101118156. Its totient is φ = 64934400.

The previous prime is 81357421. The next prime is 81357433. The reversal of 81357425 is 52475318.

It is a happy number.

It can be written as a sum of positive squares in 6 ways, for example, as 5161984 + 76195441 = 2272^2 + 8729^2 .

It is not a de Polignac number, because 81357425 - 2² = 81357421 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81357421) 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, 7865 + ... + 14985.

It is an arithmetic number, because the mean of its divisors is an integer number (8426513).

Almost surely, 2^81357425 is an apocalyptic number.

It is an amenable number.

81357425 is a deficient number, since it is larger than the sum of its proper divisors (19760731).

81357425 is a wasteful number, since it uses less digits than its factorization.

81357425 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7588 (or 7583 counting only the distinct ones).

The product of its digits is 33600, while the sum is 35.

The square root of 81357425 is about 9019.8350871842. The cubic root of 81357425 is about 433.3103521672.

The spelling of 81357425 in words is "eighty-one million, three hundred fifty-seven thousand, four hundred twenty-five".