121215906 has 96 divisors (see below), whose sum is σ = 318908160. Its totient is φ = 34020000.

The previous prime is 121215889. The next prime is 121215907. The reversal of 121215906 is 609512121.

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

It is a self number, because there is not a number n which added to its sum of digits gives 121215906.

It is not an unprimeable number, because it can be changed into a prime (121215907) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 161031 + ... + 161781.

It is an arithmetic number, because the mean of its divisors is an integer number (3321960).

Almost surely, 2^121215906 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 121215906, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (159454080).

121215906 is an abundant number, since it is smaller than the sum of its proper divisors (197692254).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

121215906 is a wasteful number, since it uses less digits than its factorization.

121215906 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 837 (or 824 counting only the distinct ones).

The product of its (nonzero) digits is 1080, while the sum is 27.

The square root of 121215906 is about 11009.8095351373. The cubic root of 121215906 is about 494.9027540831.

The spelling of 121215906 in words is "one hundred twenty-one million, two hundred fifteen thousand, nine hundred six".