81650825 has 12 divisors (see below), whose sum is σ = 102387420. Its totient is φ = 64584960.

The previous prime is 81650791. The next prime is 81650827. The reversal of 81650825 is 52805618.

It is a happy number.

It can be written as a sum of positive squares in 6 ways, for example, as 15976009 + 65674816 = 3997^2 + 8104^2 .

It is not a de Polignac number, because 81650825 - 2⁶ = 81650761 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (81650827) 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, 16124 + ... + 20573.

It is an arithmetic number, because the mean of its divisors is an integer number (8532285).

Almost surely, 2^81650825 is an apocalyptic number.

It is an amenable number.

81650825 is a deficient number, since it is larger than the sum of its proper divisors (20736595).

81650825 is a wasteful number, since it uses less digits than its factorization.

81650825 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36796 (or 36791 counting only the distinct ones).

The product of its (nonzero) digits is 19200, while the sum is 35.

The square root of 81650825 is about 9036.0846056243. The cubic root of 81650825 is about 433.8306109123.

The spelling of 81650825 in words is "eighty-one million, six hundred fifty thousand, eight hundred twenty-five".