521131818 has 16 divisors (see below), whose sum is σ = 1051488576. Its totient is φ = 172173120.

The previous prime is 521131811. The next prime is 521131843. The reversal of 521131818 is 818131125.

It is not an unprimeable number, because it can be changed into a prime (521131811) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 383638 + ... + 384993.

It is an arithmetic number, because the mean of its divisors is an integer number (65718036).

Almost surely, 2^521131818 is an apocalyptic number.

521131818 is an abundant number, since it is smaller than the sum of its proper divisors (530356758).

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

521131818 is a wasteful number, since it uses less digits than its factorization.

521131818 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 768749.

The product of its digits is 1920, while the sum is 30.

The square root of 521131818 is about 22828.3117641231. The cubic root of 521131818 is about 804.7281558342.

The spelling of 521131818 in words is "five hundred twenty-one million, one hundred thirty-one thousand, eight hundred eighteen".