81915922 has 8 divisors (see below), whose sum is σ = 134044272. Its totient is φ = 37234500.

The previous prime is 81915917. The next prime is 81915929. The reversal of 81915922 is 22951918.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a super-2 number, since 2×81915922² = 13420436554220168, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81915929) by changing a digit.

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, 1861704 + ... + 1861747.

It is an arithmetic number, because the mean of its divisors is an integer number (16755534).

Almost surely, 2^81915922 is an apocalyptic number.

81915922 is a deficient number, since it is larger than the sum of its proper divisors (52128350).

81915922 is a wasteful number, since it uses less digits than its factorization.

81915922 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3723464.

The product of its digits is 12960, while the sum is 37.

The square root of 81915922 is about 9050.7415165830. The cubic root of 81915922 is about 434.2996118982.

The spelling of 81915922 in words is "eighty-one million, nine hundred fifteen thousand, nine hundred twenty-two".