81729590 has 32 divisors (see below), whose sum is σ = 150115680. Its totient is φ = 32032000.

The previous prime is 81729589. The next prime is 81729601. The reversal of 81729590 is 9592718.

It is a Curzon number.

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, 116240 + ... + 116940.

It is an arithmetic number, because the mean of its divisors is an integer number (4691115).

Almost surely, 2^81729590 is an apocalyptic number.

81729590 is a deficient number, since it is larger than the sum of its proper divisors (68386090).

81729590 is a wasteful number, since it uses less digits than its factorization.

81729590 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 928.

The product of its (nonzero) digits is 45360, while the sum is 41.

The square root of 81729590 is about 9040.4419139774. The cubic root of 81729590 is about 433.9700652547.

The spelling of 81729590 in words is "eighty-one million, seven hundred twenty-nine thousand, five hundred ninety".