213406561 has 4 divisors (see below), whose sum is σ = 214942000. Its totient is φ = 211871124.

The previous prime is 213406547. The next prime is 213406579. The reversal of 213406561 is 165604312.

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 a cyclic number.

It is not a de Polignac number, because 213406561 - 2⁷ = 213406433 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (213406541) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 767511 + ... + 767788.

It is an arithmetic number, because the mean of its divisors is an integer number (53735500).

Almost surely, 2^213406561 is an apocalyptic number.

It is an amenable number.

213406561 is a deficient number, since it is larger than the sum of its proper divisors (1535439).

213406561 is a wasteful number, since it uses less digits than its factorization.

213406561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1535438.

The product of its (nonzero) digits is 4320, while the sum is 28.

The square root of 213406561 is about 14608.4414295297. The cubic root of 213406561 is about 597.5889923060.

The spelling of 213406561 in words is "two hundred thirteen million, four hundred six thousand, five hundred sixty-one".