81759390 has 32 divisors (see below), whose sum is σ = 199928736. Its totient is φ = 21390720.

The previous prime is 81759361. The next prime is 81759397. The reversal of 81759390 is 9395718.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81759397) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 24121 + ... + 27300.

It is an arithmetic number, because the mean of its divisors is an integer number (6247773).

Almost surely, 2^81759390 is an apocalyptic number.

81759390 is an abundant number, since it is smaller than the sum of its proper divisors (118169346).

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

81759390 is a wasteful number, since it uses less digits than its factorization.

81759390 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51484.

The product of its (nonzero) digits is 68040, while the sum is 42.

The square root of 81759390 is about 9042.0899132889. The cubic root of 81759390 is about 434.0228031369.

The spelling of 81759390 in words is "eighty-one million, seven hundred fifty-nine thousand, three hundred ninety".