81938315 has 8 divisors (see below), whose sum is σ = 99992880. Its totient is φ = 64439392.

The previous prime is 81938303. The next prime is 81938321. The reversal of 81938315 is 51383918.

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

It is a cyclic number.

It is not a de Polignac number, because 81938315 - 2⁴ = 81938299 is a prime.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 138584 + ... + 139173.

It is an arithmetic number, because the mean of its divisors is an integer number (12499110).

Almost surely, 2^81938315 is an apocalyptic number.

81938315 is a deficient number, since it is larger than the sum of its proper divisors (18054565).

81938315 is a wasteful number, since it uses less digits than its factorization.

81938315 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 277821.

The product of its digits is 25920, while the sum is 38.

The square root of 81938315 is about 9051.9785130103. The cubic root of 81938315 is about 434.3391824925.

The spelling of 81938315 in words is "eighty-one million, nine hundred thirty-eight thousand, three hundred fifteen".