81408933 has 12 divisors (see below), whose sum is σ = 120325920. Its totient is φ = 53010216.

The previous prime is 81408911. The next prime is 81408949. The reversal of 81408933 is 33980418.

It is not a de Polignac number, because 81408933 - 2⁹ = 81408421 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81408233) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 104793 + ... + 105566.

It is an arithmetic number, because the mean of its divisors is an integer number (10027160).

Almost surely, 2^81408933 is an apocalyptic number.

It is an amenable number.

81408933 is a deficient number, since it is larger than the sum of its proper divisors (38916987).

81408933 is a wasteful number, since it uses less digits than its factorization.

81408933 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 210408 (or 210405 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 36.

The square root of 81408933 is about 9022.6898982510. The cubic root of 81408933 is about 433.4017768945.

The spelling of 81408933 in words is "eighty-one million, four hundred eight thousand, nine hundred thirty-three".