121661904 has 240 divisors, whose sum is σ = 413223552. Its totient is φ = 30514176.

The previous prime is 121661867. The next prime is 121661909. The reversal of 121661904 is 409166121.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121661909) 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 47 ways as a sum of consecutive naturals, for example, 703162 + ... + 703334.

Almost surely, 2^121661904 is an apocalyptic number.

121661904 is a gapful number since it is divisible by the number (14) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 121661904, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (206611776).

121661904 is an abundant number, since it is smaller than the sum of its proper divisors (291561648).

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

121661904 is a wasteful number, since it uses less digits than its factorization.

121661904 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 234 (or 221 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 30.

The square root of 121661904 is about 11030.0455121455. The cubic root of 121661904 is about 495.5089877243.

The spelling of 121661904 in words is "one hundred twenty-one million, six hundred sixty-one thousand, nine hundred four".