81621116 has 12 divisors (see below), whose sum is σ = 142953888. Its totient is φ = 40777152.

The previous prime is 81621107. The next prime is 81621191. The reversal of 81621116 is 61112618.

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, 2381 + ... + 12996.

It is an arithmetic number, because the mean of its divisors is an integer number (11912824).

Almost surely, 2^81621116 is an apocalyptic number.

It is an amenable number.

81621116 is a deficient number, since it is larger than the sum of its proper divisors (61332772).

81621116 is a wasteful number, since it uses less digits than its factorization.

81621116 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16708 (or 16706 counting only the distinct ones).

The product of its digits is 576, while the sum is 26.

The square root of 81621116 is about 9034.4405471507. The cubic root of 81621116 is about 433.7779874917. Note that the first 3 decimals are identical.

The spelling of 81621116 in words is "eighty-one million, six hundred twenty-one thousand, one hundred sixteen".