213545621 has 4 divisors (see below), whose sum is σ = 215945100. Its totient is φ = 211146144.

The previous prime is 213545609. The next prime is 213545663. The reversal of 213545621 is 126545312.

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 76912900 + 136632721 = 8770^2 + 11689^2 .

It is a cyclic number.

It is not a de Polignac number, because 213545621 - 2¹⁴ = 213529237 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (213545681) 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, 1199606 + ... + 1199783.

It is an arithmetic number, because the mean of its divisors is an integer number (53986275).

Almost surely, 2^213545621 is an apocalyptic number.

It is an amenable number.

213545621 is a deficient number, since it is larger than the sum of its proper divisors (2399479).

213545621 is an equidigital number, since it uses as much as digits as its factorization.

213545621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2399478.

The product of its digits is 7200, while the sum is 29.

The square root of 213545621 is about 14613.2002312977. The cubic root of 213545621 is about 597.7187644514.

The spelling of 213545621 in words is "two hundred thirteen million, five hundred forty-five thousand, six hundred twenty-one".