81838325 has 6 divisors (see below), whose sum is σ = 101479554. Its totient is φ = 65470640.

The previous prime is 81838321. The next prime is 81838333. The reversal of 81838325 is 52383818.

It can be written as a sum of positive squares in 3 ways, for example, as 152881 + 81685444 = 391^2 + 9038^2 .

It is not a de Polignac number, because 81838325 - 2² = 81838321 is a prime.

It is a super-2 number, since 2×81838325² = 13395022877611250, which contains 22 as substring.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81838321) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1636742 + ... + 1636791.

It is an arithmetic number, because the mean of its divisors is an integer number (16913259).

Almost surely, 2^81838325 is an apocalyptic number.

It is an amenable number.

81838325 is a deficient number, since it is larger than the sum of its proper divisors (19641229).

81838325 is a wasteful number, since it uses less digits than its factorization.

81838325 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3273543 (or 3273538 counting only the distinct ones).

The product of its digits is 46080, while the sum is 38.

The square root of 81838325 is about 9046.4537250792. The cubic root of 81838325 is about 434.1624346847.

The spelling of 81838325 in words is "eighty-one million, eight hundred thirty-eight thousand, three hundred twenty-five".