81624513 has 16 divisors (see below), whose sum is σ = 115681280. Its totient is φ = 51048144.

The previous prime is 81624509. The next prime is 81624523. The reversal of 81624513 is 31542618.

It is not a de Polignac number, because 81624513 - 2² = 81624509 is a prime.

It is a super-2 number, since 2×81624513² = 13325122244974338, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81624523) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1081 + ... + 12822.

It is an arithmetic number, because the mean of its divisors is an integer number (7230080).

Almost surely, 2^81624513 is an apocalyptic number.

It is an amenable number.

81624513 is a deficient number, since it is larger than the sum of its proper divisors (34056767).

81624513 is a wasteful number, since it uses less digits than its factorization.

81624513 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14028.

The product of its digits is 5760, while the sum is 30.

The square root of 81624513 is about 9034.6285479814. The cubic root of 81624513 is about 433.7840052293.

The spelling of 81624513 in words is "eighty-one million, six hundred twenty-four thousand, five hundred thirteen".