81707238 has 32 divisors (see below), whose sum is σ = 185004000. Its totient is φ = 26720928.

The previous prime is 81707209. The next prime is 81707257. The reversal of 81707238 is 83270718.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11413 + ... + 17136.

It is an arithmetic number, because the mean of its divisors is an integer number (5781375).

Almost surely, 2^81707238 is an apocalyptic number.

81707238 is an abundant number, since it is smaller than the sum of its proper divisors (103296762).

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

81707238 is a wasteful number, since it uses less digits than its factorization.

81707238 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28613 (or 28607 counting only the distinct ones).

The product of its (nonzero) digits is 18816, while the sum is 36.

The square root of 81707238 is about 9039.2056066891. The cubic root of 81707238 is about 433.9304998891.

The spelling of 81707238 in words is "eighty-one million, seven hundred seven thousand, two hundred thirty-eight".