213668409 has 4 divisors (see below), whose sum is σ = 284891216. Its totient is φ = 142445604.

The previous prime is 213668401. The next prime is 213668417. The reversal of 213668409 is 904866312.

213668409 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is an interprime number because it is at equal distance from previous prime (213668401) and next prime (213668417).

It is not a de Polignac number, because 213668409 - 2³ = 213668401 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (213668401) 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, 35611399 + ... + 35611404.

It is an arithmetic number, because the mean of its divisors is an integer number (71222804).

Almost surely, 2^213668409 is an apocalyptic number.

It is an amenable number.

213668409 is a deficient number, since it is larger than the sum of its proper divisors (71222807).

213668409 is an equidigital number, since it uses as much as digits as its factorization.

213668409 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 71222806.

The product of its (nonzero) digits is 62208, while the sum is 39.

The square root of 213668409 is about 14617.4008975604. The cubic root of 213668409 is about 597.8333045810.

The spelling of 213668409 in words is "two hundred thirteen million, six hundred sixty-eight thousand, four hundred nine".