81520734 has 8 divisors (see below), whose sum is σ = 163041480. Its totient is φ = 27173576.

The previous prime is 81520727. The next prime is 81520739. The reversal of 81520734 is 43702518.

It is a sphenic number, since it is the product of 3 distinct primes.

81520734 is an admirable number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81520739) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6793389 + ... + 6793400.

It is an arithmetic number, because the mean of its divisors is an integer number (20380185).

Almost surely, 2^81520734 is an apocalyptic number.

81520734 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

81520734 is a wasteful number, since it uses less digits than its factorization.

81520734 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13586794.

The product of its (nonzero) digits is 6720, while the sum is 30.

The square root of 81520734 is about 9028.8833196581. The cubic root of 81520734 is about 433.6000867760.

The spelling of 81520734 in words is "eighty-one million, five hundred twenty thousand, seven hundred thirty-four".