81825424 has 10 divisors (see below), whose sum is σ = 158536790. Its totient is φ = 40912704.

The previous prime is 81825413. The next prime is 81825427. The reversal of 81825424 is 42452818.

It can be written as a sum of positive squares in only one way, i.e., 67897600 + 13927824 = 8240^2 + 3732^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 81825424.

It is not an unprimeable number, because it can be changed into a prime (81825427) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2557029 + ... + 2557060.

It is an arithmetic number, because the mean of its divisors is an integer number (15853679).

Almost surely, 2^81825424 is an apocalyptic number.

It is an amenable number.

81825424 is a deficient number, since it is larger than the sum of its proper divisors (76711366).

81825424 is a wasteful number, since it uses less digits than its factorization.

81825424 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5114097 (or 5114091 counting only the distinct ones).

The product of its digits is 20480, while the sum is 34.

The square root of 81825424 is about 9045.7406551371. The cubic root of 81825424 is about 434.1396196857.

The spelling of 81825424 in words is "eighty-one million, eight hundred twenty-five thousand, four hundred twenty-four".