121857213 has 4 divisors (see below), whose sum is σ = 162476288. Its totient is φ = 81238140.

The previous prime is 121857209. The next prime is 121857247. The reversal of 121857213 is 312758121.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 121857213 - 2² = 121857209 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 (121855213) 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, 20309533 + ... + 20309538.

It is an arithmetic number, because the mean of its divisors is an integer number (40619072).

Almost surely, 2^121857213 is an apocalyptic number.

It is an amenable number.

121857213 is a deficient number, since it is larger than the sum of its proper divisors (40619075).

121857213 is an equidigital number, since it uses as much as digits as its factorization.

121857213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40619074.

The product of its digits is 3360, while the sum is 30.

The square root of 121857213 is about 11038.8954610504. The cubic root of 121857213 is about 495.7739998080.

The spelling of 121857213 in words is "one hundred twenty-one million, eight hundred fifty-seven thousand, two hundred thirteen".