121917618 has 48 divisors (see below), whose sum is σ = 277333056. Its totient is φ = 38633760.

The previous prime is 121917617. The next prime is 121917667. The reversal of 121917618 is 816719121.

121917618 is a `hidden beast` number, since 1 + 21 + 9 + 17 + 618 = 666.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (121917613) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 74121 + ... + 75747.

It is an arithmetic number, because the mean of its divisors is an integer number (5777772).

Almost surely, 2^121917618 is an apocalyptic number.

121917618 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 121917618, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (138666528).

121917618 is an abundant number, since it is smaller than the sum of its proper divisors (155415438).

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

121917618 is a wasteful number, since it uses less digits than its factorization.

121917618 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1839 (or 1836 counting only the distinct ones).

The product of its digits is 6048, while the sum is 36.

The square root of 121917618 is about 11041.6311295026. The cubic root of 121917618 is about 495.8559051812.

The spelling of 121917618 in words is "one hundred twenty-one million, nine hundred seventeen thousand, six hundred eighteen".