213454921 has 4 divisors (see below), whose sum is σ = 216954244. Its totient is φ = 209955600.

The previous prime is 213454909. The next prime is 213454939. The reversal of 213454921 is 129454312.

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 10791225 + 202663696 = 3285^2 + 14236^2 .

It is a cyclic number.

It is not a de Polignac number, because 213454921 - 2⁵ = 213454889 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (213454981) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1749570 + ... + 1749691.

It is an arithmetic number, because the mean of its divisors is an integer number (54238561).

Almost surely, 2^213454921 is an apocalyptic number.

It is an amenable number.

213454921 is a deficient number, since it is larger than the sum of its proper divisors (3499323).

213454921 is an equidigital number, since it uses as much as digits as its factorization.

213454921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3499322.

The product of its digits is 8640, while the sum is 31.

The square root of 213454921 is about 14610.0965431444. The cubic root of 213454921 is about 597.6341287205.

The spelling of 213454921 in words is "two hundred thirteen million, four hundred fifty-four thousand, nine hundred twenty-one".