81890884 has 12 divisors (see below), whose sum is σ = 145448464. Its totient is φ = 40334184.

The previous prime is 81890881. The next prime is 81890891. The reversal of 81890884 is 48809818.

It is a super-2 number, since 2×81890884² = 13412233764602912, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81890881) 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, 152514 + ... + 153049.

Almost surely, 2^81890884 is an apocalyptic number.

It is an amenable number.

81890884 is a deficient number, since it is larger than the sum of its proper divisors (63557580).

81890884 is a wasteful number, since it uses less digits than its factorization.

81890884 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 305634 (or 305632 counting only the distinct ones).

The product of its (nonzero) digits is 147456, while the sum is 46.

The square root of 81890884 is about 9049.3582092876. The cubic root of 81890884 is about 434.2553587929.

The spelling of 81890884 in words is "eighty-one million, eight hundred ninety thousand, eight hundred eighty-four".