81624445 has 12 divisors (see below), whose sum is σ = 113941404. Its totient is φ = 55970880.

The previous prime is 81624443. The next prime is 81624461. The reversal of 81624445 is 54442618.

It can be written as a sum of positive squares in 2 ways, for example, as 44876601 + 36747844 = 6699^2 + 6062^2 .

It is not a de Polignac number, because 81624445 - 2¹ = 81624443 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 81624445.

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 pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 166336 + ... + 166825.

It is an arithmetic number, because the mean of its divisors is an integer number (9495117).

Almost surely, 2^81624445 is an apocalyptic number.

It is an amenable number.

81624445 is a deficient number, since it is larger than the sum of its proper divisors (32316959).

81624445 is a wasteful number, since it uses less digits than its factorization.

81624445 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 333180 (or 333173 counting only the distinct ones).

The product of its digits is 30720, while the sum is 34.

The square root of 81624445 is about 9034.6247846825. The cubic root of 81624445 is about 433.7838847699.

It can be divided in two parts, 8162444 and 5, that added together give a square (8162449 = 2857²).

The spelling of 81624445 in words is "eighty-one million, six hundred twenty-four thousand, four hundred forty-five".