81924444 has 72 divisors (see below), whose sum is σ = 244328448. Its totient is φ = 22649760.

The previous prime is 81924439. The next prime is 81924463. The reversal of 81924444 is 44442918.

It is a super-2 number, since 2×81924444² = 13423229049418272, which contains 22 as substring.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 81924399 and 81924408.

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 23 ways as a sum of consecutive naturals, for example, 2569 + ... + 13055.

Almost surely, 2^81924444 is an apocalyptic number.

81924444 is a gapful number since it is divisible by the number (84) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81924444, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (122164224).

81924444 is an abundant number, since it is smaller than the sum of its proper divisors (162404004).

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

81924444 is a wasteful number, since it uses less digits than its factorization.

81924444 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10535 (or 10530 counting only the distinct ones).

The product of its digits is 36864, while the sum is 36.

The square root of 81924444 is about 9051.2122944940. The cubic root of 81924444 is about 434.3146719454.

The spelling of 81924444 in words is "eighty-one million, nine hundred twenty-four thousand, four hundred forty-four".