81373929 has 32 divisors (see below), whose sum is σ = 134077440. Its totient is φ = 42748992.

The previous prime is 81373927. The next prime is 81373933. The reversal of 81373929 is 92937318.

It is not a de Polignac number, because 81373929 - 2¹ = 81373927 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81373927) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 94302 + ... + 95160.

It is an arithmetic number, because the mean of its divisors is an integer number (4189920).

Almost surely, 2^81373929 is an apocalyptic number.

It is an amenable number.

81373929 is a deficient number, since it is larger than the sum of its proper divisors (52703511).

81373929 is a wasteful number, since it uses less digits than its factorization.

81373929 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1229.

The product of its digits is 81648, while the sum is 42.

The square root of 81373929 is about 9020.7499133941. The cubic root of 81373929 is about 433.3396503353.

The spelling of 81373929 in words is "eighty-one million, three hundred seventy-three thousand, nine hundred twenty-nine".