121816251 has 16 divisors (see below), whose sum is σ = 183164800. Its totient is φ = 79997544.

The previous prime is 121816243. The next prime is 121816259. The reversal of 121816251 is 152618121.

It is an interprime number because it is at equal distance from previous prime (121816243) and next prime (121816259).

It is not a de Polignac number, because 121816251 - 2³ = 121816243 is a prime.

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

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (121816259) 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, 31861 + ... + 35478.

It is an arithmetic number, because the mean of its divisors is an integer number (11447800).

Almost surely, 2^121816251 is an apocalyptic number.

121816251 is a deficient number, since it is larger than the sum of its proper divisors (61348549).

121816251 is an equidigital number, since it uses as much as digits as its factorization.

121816251 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 67415 (or 67409 counting only the distinct ones).

The product of its digits is 960, while the sum is 27.

The square root of 121816251 is about 11037.0399564376. The cubic root of 121816251 is about 495.7184425155.

The spelling of 121816251 in words is "one hundred twenty-one million, eight hundred sixteen thousand, two hundred fifty-one".