81733788 has 18 divisors (see below), whose sum is σ = 206604944. Its totient is φ = 27244584.

The previous prime is 81733753. The next prime is 81733811. The reversal of 81733788 is 88733718.

It is a tau number, because it is divible by the number of its divisors (18).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1135156 + ... + 1135227.

Almost surely, 2^81733788 is an apocalyptic number.

It is an amenable number.

81733788 is an abundant number, since it is smaller than the sum of its proper divisors (124871156).

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

81733788 is a wasteful number, since it uses less digits than its factorization.

81733788 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2270393 (or 2270388 counting only the distinct ones).

The product of its digits is 225792, while the sum is 45.

The square root of 81733788 is about 9040.6740899117. The cubic root of 81733788 is about 433.9774953468.

The spelling of 81733788 in words is "eighty-one million, seven hundred thirty-three thousand, seven hundred eighty-eight".