81624444 has 48 divisors (see below), whose sum is σ = 214945920. Its totient is φ = 23880640.

The previous prime is 81624443. The next prime is 81624461. The reversal of 81624444 is 44442618.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81624443) 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, 6834 + ... + 14489.

It is an arithmetic number, because the mean of its divisors is an integer number (4478040).

Almost surely, 2^81624444 is an apocalyptic number.

It is an amenable number.

81624444 is an abundant number, since it is smaller than the sum of its proper divisors (133321476).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81624444 is a wasteful number, since it uses less digits than its factorization.

81624444 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21370 (or 21368 counting only the distinct ones).

The product of its digits is 24576, while the sum is 33.

The square root of 81624444 is about 9034.6247293399. The cubic root of 81624444 is about 433.7838829984.

The spelling of 81624444 in words is "eighty-one million, six hundred twenty-four thousand, four hundred forty-four".