81903879 has 28 divisors (see below), whose sum is σ = 123543976. Its totient is φ = 54272592.

The previous prime is 81903847. The next prime is 81903881. The reversal of 81903879 is 97830918.

It is not a de Polignac number, because 81903879 - 2⁵ = 81903847 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81903839) 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 27 ways as a sum of consecutive naturals, for example, 206109 + ... + 206505.

Almost surely, 2^81903879 is an apocalyptic number.

81903879 is a deficient number, since it is larger than the sum of its proper divisors (41640097).

81903879 is an equidigital number, since it uses as much as digits as its factorization.

81903879 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 698 (or 683 counting only the distinct ones).

The product of its (nonzero) digits is 108864, while the sum is 45.

The square root of 81903879 is about 9050.0761875246. The cubic root of 81903879 is about 434.2783277716.

The spelling of 81903879 in words is "eighty-one million, nine hundred three thousand, eight hundred seventy-nine".