121257906 has 64 divisors (see below), whose sum is σ = 320163840. Its totient is φ = 29640960.

The previous prime is 121257881. The next prime is 121257907. The reversal of 121257906 is 609752121.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is not an unprimeable number, because it can be changed into a prime (121257907) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 135 + ... + 15573.

It is an arithmetic number, because the mean of its divisors is an integer number (5002560).

Almost surely, 2^121257906 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 121257906, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (160081920).

121257906 is an abundant number, since it is smaller than the sum of its proper divisors (198905934).

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

121257906 is a wasteful number, since it uses less digits than its factorization.

121257906 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15479.

The product of its (nonzero) digits is 7560, while the sum is 33.

The square root of 121257906 is about 11011.7167598881. The cubic root of 121257906 is about 494.9599069660.

The spelling of 121257906 in words is "one hundred twenty-one million, two hundred fifty-seven thousand, nine hundred six".