121855213 has 2 divisors, whose sum is σ = 121855214. Its totient is φ = 121855212.

The previous prime is 121855211. The next prime is 121855231. The reversal of 121855213 is 312558121.

Together with next prime (121855231) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 65334889 + 56520324 = 8083^2 + 7518^2 .

It is a cyclic number.

It is not a de Polignac number, because 121855213 - 2¹ = 121855211 is a prime.

Together with 121855211, it forms a pair of twin primes.

It is equal to p_6941224 and since 121855213 and 6941224 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (121855211) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 60927606 + 60927607.

It is an arithmetic number, because the mean of its divisors is an integer number (60927607).

Almost surely, 2^121855213 is an apocalyptic number.

It is an amenable number.

121855213 is a deficient number, since it is larger than the sum of its proper divisors (1).

121855213 is an equidigital number, since it uses as much as digits as its factorization.

121855213 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2400, while the sum is 28.

The square root of 121855213 is about 11038.8048719053. The cubic root of 121855213 is about 495.7712874712.

The spelling of 121855213 in words is "one hundred twenty-one million, eight hundred fifty-five thousand, two hundred thirteen".