121661421 has 16 divisors (see below), whose sum is σ = 193449984. Its totient is φ = 66497904.

The previous prime is 121661399. The next prime is 121661429. The reversal of 121661421 is 124166121.

It is a happy number.

It is not a de Polignac number, because 121661421 - 2⁶ = 121661357 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 121661391 and 121661400.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121661429) 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, 125461 + ... + 126426.

It is an arithmetic number, because the mean of its divisors is an integer number (12090624).

Almost surely, 2^121661421 is an apocalyptic number.

It is an amenable number.

121661421 is a deficient number, since it is larger than the sum of its proper divisors (71788563).

121661421 is a wasteful number, since it uses less digits than its factorization.

121661421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 251920.

The product of its digits is 576, while the sum is 24.

The square root of 121661421 is about 11030.0236173818. The cubic root of 121661421 is about 495.5083319968.

The spelling of 121661421 in words is "one hundred twenty-one million, six hundred sixty-one thousand, four hundred twenty-one".