213885409 has 2 divisors, whose sum is σ = 213885410. Its totient is φ = 213885408.

The previous prime is 213885407. The next prime is 213885433. The reversal of 213885409 is 904588312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 170694225 + 43191184 = 13065^2 + 6572^2 .

It is a cyclic number.

It is not a de Polignac number, because 213885409 - 2¹ = 213885407 is a prime.

Together with 213885407, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (213885407) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106942704 + 106942705.

It is an arithmetic number, because the mean of its divisors is an integer number (106942705).

Almost surely, 2^213885409 is an apocalyptic number.

It is an amenable number.

213885409 is a deficient number, since it is larger than the sum of its proper divisors (1).

213885409 is an equidigital number, since it uses as much as digits as its factorization.

213885409 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 69120, while the sum is 40.

The square root of 213885409 is about 14624.8216741265. The cubic root of 213885409 is about 598.0356210814.

The spelling of 213885409 in words is "two hundred thirteen million, eight hundred eighty-five thousand, four hundred nine".