213890309 has 4 divisors (see below), whose sum is σ = 214384716. Its totient is φ = 213395904.

The previous prime is 213890249. The next prime is 213890323. The reversal of 213890309 is 903098312.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 67601284 + 146289025 = 8222^2 + 12095^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-213890309 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (213880309) 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, 246554 + ... + 247419.

It is an arithmetic number, because the mean of its divisors is an integer number (53596179).

Almost surely, 2^213890309 is an apocalyptic number.

It is an amenable number.

213890309 is a deficient number, since it is larger than the sum of its proper divisors (494407).

213890309 is an equidigital number, since it uses as much as digits as its factorization.

213890309 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 494406.

The product of its (nonzero) digits is 11664, while the sum is 35.

The square root of 213890309 is about 14624.9891965772. The cubic root of 213890309 is about 598.0401879383.

The spelling of 213890309 in words is "two hundred thirteen million, eight hundred ninety thousand, three hundred nine".