81204825 has 48 divisors (see below), whose sum is σ = 148559936. Its totient is φ = 38880000.

The previous prime is 81204821. The next prime is 81204857. The reversal of 81204825 is 52840218.

It is not a de Polignac number, because 81204825 - 2² = 81204821 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81204792 and 81204801.

It is not an unprimeable number, because it can be changed into a prime (81204821) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 34950 + ... + 37200.

Almost surely, 2^81204825 is an apocalyptic number.

It is an amenable number.

81204825 is a deficient number, since it is larger than the sum of its proper divisors (67355111).

81204825 is a wasteful number, since it uses less digits than its factorization.

81204825 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2314 (or 2309 counting only the distinct ones).

The product of its (nonzero) digits is 5120, while the sum is 30.

The square root of 81204825 is about 9011.3719821124. The cubic root of 81204825 is about 433.0392662984.

The spelling of 81204825 in words is "eighty-one million, two hundred four thousand, eight hundred twenty-five".