81959885 has 16 divisors (see below), whose sum is σ = 112829952. Its totient is φ = 55987200.

The previous prime is 81959837. The next prime is 81959897. The reversal of 81959885 is 58895918.

It is not a de Polignac number, because 81959885 - 2¹⁰ = 81958861 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5165 + ... + 13805.

It is an arithmetic number, because the mean of its divisors is an integer number (7051872).

Almost surely, 2^81959885 is an apocalyptic number.

It is an amenable number.

81959885 is a deficient number, since it is larger than the sum of its proper divisors (30870067).

81959885 is a wasteful number, since it uses less digits than its factorization.

81959885 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8924.

The product of its digits is 1036800, while the sum is 53.

The square root of 81959885 is about 9053.1698868407. The cubic root of 81959885 is about 434.3772919500.

The spelling of 81959885 in words is "eighty-one million, nine hundred fifty-nine thousand, eight hundred eighty-five".