81799325 has 24 divisors (see below), whose sum is σ = 108053352. Its totient is φ = 61214720.

The previous prime is 81799307. The next prime is 81799327. The reversal of 81799325 is 52399718.

It can be written as a sum of positive squares in 12 ways, for example, as 3193369 + 78605956 = 1787^2 + 8866^2 .

It is not a de Polignac number, because 81799325 - 2⁶ = 81799261 is a prime.

It is a super-2 number, since 2×81799325² = 13382259140911250, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81799327) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 83237 + ... + 84213.

It is an arithmetic number, because the mean of its divisors is an integer number (4502223).

Almost surely, 2^81799325 is an apocalyptic number.

81799325 is a gapful number since it is divisible by the number (85) formed by its first and last digit.

It is an amenable number.

81799325 is a deficient number, since it is larger than the sum of its proper divisors (26254027).

81799325 is a wasteful number, since it uses less digits than its factorization.

81799325 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1201 (or 1196 counting only the distinct ones).

The product of its digits is 136080, while the sum is 44.

The square root of 81799325 is about 9044.2979274237. The cubic root of 81799325 is about 434.0934571188.

The spelling of 81799325 in words is "eighty-one million, seven hundred ninety-nine thousand, three hundred twenty-five".