213906921 has 16 divisors (see below), whose sum is σ = 301055040. Its totient is φ = 134723520.

The previous prime is 213906911. The next prime is 213906943. The reversal of 213906921 is 129609312.

It is not a de Polignac number, because 213906921 - 2¹⁹ = 213382633 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (213906911) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 16231 + ... + 26291.

It is an arithmetic number, because the mean of its divisors is an integer number (18815940).

Almost surely, 2^213906921 is an apocalyptic number.

It is an amenable number.

213906921 is a deficient number, since it is larger than the sum of its proper divisors (87148119).

213906921 is a wasteful number, since it uses less digits than its factorization.

213906921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10456.

The product of its (nonzero) digits is 5832, while the sum is 33.

The square root of 213906921 is about 14625.5571175938. The cubic root of 213906921 is about 598.0556699962.

The spelling of 213906921 in words is "two hundred thirteen million, nine hundred six thousand, nine hundred twenty-one".