213399521 has 12 divisors (see below), whose sum is σ = 227803212. Its totient is φ = 199213056.

The previous prime is 213399509. The next prime is 213399523. The reversal of 213399521 is 125993312.

It can be written as a sum of positive squares in 6 ways, for example, as 12327121 + 201072400 = 3511^2 + 14180^2 .

It is not a de Polignac number, because 213399521 - 2¹⁸ = 213137377 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (213399523) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 633065 + ... + 633401.

It is an arithmetic number, because the mean of its divisors is an integer number (18983601).

Almost surely, 2^213399521 is an apocalyptic number.

It is an amenable number.

213399521 is a deficient number, since it is larger than the sum of its proper divisors (14403691).

213399521 is an equidigital number, since it uses as much as digits as its factorization.

213399521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 740 (or 547 counting only the distinct ones).

The product of its digits is 14580, while the sum is 35.

The square root of 213399521 is about 14608.2004709684. The cubic root of 213399521 is about 597.5824210105.

The spelling of 213399521 in words is "two hundred thirteen million, three hundred ninety-nine thousand, five hundred twenty-one".