121665213 has 16 divisors (see below), whose sum is σ = 185117760. Its totient is φ = 78917328.

The previous prime is 121665169. The next prime is 121665241. The reversal of 121665213 is 312566121.

121665213 is a `hidden beast` number, since 1 + 2 + 1 + 6 + 652 + 1 + 3 = 666.

It is not a de Polignac number, because 121665213 - 2⁶ = 121665149 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121665253) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 59895 + ... + 61892.

It is an arithmetic number, because the mean of its divisors is an integer number (11569860).

Almost surely, 2^121665213 is an apocalyptic number.

It is an amenable number.

121665213 is a deficient number, since it is larger than the sum of its proper divisors (63452547).

121665213 is a wasteful number, since it uses less digits than its factorization.

121665213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 121833 (or 121827 counting only the distinct ones).

The product of its digits is 2160, while the sum is 27.

The square root of 121665213 is about 11030.1955105066. The cubic root of 121665213 is about 495.5134800217.

The spelling of 121665213 in words is "one hundred twenty-one million, six hundred sixty-five thousand, two hundred thirteen".