81623955 has 24 divisors (see below), whose sum is σ = 151921872. Its totient is φ = 37313472.

The previous prime is 81623939. The next prime is 81623977. The reversal of 81623955 is 55932618.

It is not a de Polignac number, because 81623955 - 2⁴ = 81623939 is a prime.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 54792 + ... + 56261.

It is an arithmetic number, because the mean of its divisors is an integer number (6330078).

Almost surely, 2^81623955 is an apocalyptic number.

81623955 is a deficient number, since it is larger than the sum of its proper divisors (70297917).

81623955 is a wasteful number, since it uses less digits than its factorization.

81623955 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 111075 (or 111068 counting only the distinct ones).

The product of its digits is 64800, while the sum is 39.

The square root of 81623955 is about 9034.5976667475. The cubic root of 81623955 is about 433.7830167516.

The spelling of 81623955 in words is "eighty-one million, six hundred twenty-three thousand, nine hundred fifty-five".