213555121 has 4 divisors (see below), whose sum is σ = 229982452. Its totient is φ = 197127792.

The previous prime is 213555077. The next prime is 213555127. The reversal of 213555121 is 121555312.

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 61402896 + 152152225 = 7836^2 + 12335^2 .

It is a cyclic number.

It is not a de Polignac number, because 213555121 - 2⁷ = 213554993 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (213555127) 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, 8213646 + ... + 8213671.

It is an arithmetic number, because the mean of its divisors is an integer number (57495613).

Almost surely, 2^213555121 is an apocalyptic number.

It is an amenable number.

213555121 is a deficient number, since it is larger than the sum of its proper divisors (16427331).

213555121 is a wasteful number, since it uses less digits than its factorization.

213555121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16427330.

The product of its digits is 1500, while the sum is 25.

The square root of 213555121 is about 14613.5252762638. The cubic root of 213555121 is about 597.7276278877.

The spelling of 213555121 in words is "two hundred thirteen million, five hundred fifty-five thousand, one hundred twenty-one".