81221488 has 20 divisors (see below), whose sum is σ = 162443968. Its totient is φ = 39300480.

The previous prime is 81221471. The next prime is 81221507. The reversal of 81221488 is 88412218.

81221488 is an admirable number.

It is a super-2 number, since 2×81221488² = 13193860225868288, which contains 22 as substring.

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 81381 + ... + 82372.

Almost surely, 2^81221488 is an apocalyptic number.

It is an amenable number.

81221488 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81221488 is a wasteful number, since it uses less digits than its factorization.

81221488 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 163792 (or 163786 counting only the distinct ones).

The product of its digits is 8192, while the sum is 34.

The square root of 81221488 is about 9012.2964886870. The cubic root of 81221488 is about 433.0688837495.

The spelling of 81221488 in words is "eighty-one million, two hundred twenty-one thousand, four hundred eighty-eight".