81340624 has 20 divisors (see below), whose sum is σ = 157881636. Its totient is φ = 40596992.

The previous prime is 81340619. The next prime is 81340657. The reversal of 81340624 is 42604318.

It can be written as a sum of positive squares in 2 ways, for example, as 38044224 + 43296400 = 6168^2 + 6580^2 .

It is a super-2 number, since 2×81340624² = 13232594225418752, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 81340592 and 81340601.

It is a congruent number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 5202 + ... + 13774.

Almost surely, 2^81340624 is an apocalyptic number.

It is an amenable number.

81340624 is a deficient number, since it is larger than the sum of its proper divisors (76541012).

81340624 is a wasteful number, since it uses less digits than its factorization.

81340624 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9174 (or 9168 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 28.

The square root of 81340624 is about 9018.9037027790. The cubic root of 81340624 is about 433.2805226898.

The spelling of 81340624 in words is "eighty-one million, three hundred forty thousand, six hundred twenty-four".