213123101 has 4 divisors (see below), whose sum is σ = 225659772. Its totient is φ = 200586432.

The previous prime is 213123077. The next prime is 213123103. The reversal of 213123101 is 101321312.

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 115132900 + 97990201 = 10730^2 + 9899^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-213123101 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (213123103) 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, 6268310 + ... + 6268343.

It is an arithmetic number, because the mean of its divisors is an integer number (56414943).

Almost surely, 2^213123101 is an apocalyptic number.

It is an amenable number.

213123101 is a deficient number, since it is larger than the sum of its proper divisors (12536671).

213123101 is a wasteful number, since it uses less digits than its factorization.

213123101 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12536670.

The product of its (nonzero) digits is 36, while the sum is 14.

The square root of 213123101 is about 14598.7362809251. The cubic root of 213123101 is about 597.3242899938.

Adding to 213123101 its reverse (101321312), we get a palindrome (314444413).

The spelling of 213123101 in words is "two hundred thirteen million, one hundred twenty-three thousand, one hundred one".