121990406 has 16 divisors (see below), whose sum is σ = 191123280. Its totient is φ = 58338720.

The previous prime is 121990403. The next prime is 121990409. The reversal of 121990406 is 604099121.

It is an interprime number because it is at equal distance from previous prime (121990403) and next prime (121990409).

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121990403) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9605 + ... + 18336.

It is an arithmetic number, because the mean of its divisors is an integer number (11945205).

Almost surely, 2^121990406 is an apocalyptic number.

121990406 is a deficient number, since it is larger than the sum of its proper divisors (69132874).

121990406 is a wasteful number, since it uses less digits than its factorization.

121990406 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28039.

The product of its (nonzero) digits is 3888, while the sum is 32.

The square root of 121990406 is about 11044.9267086749. The cubic root of 121990406 is about 495.9545651887.

The spelling of 121990406 in words is "one hundred twenty-one million, nine hundred ninety thousand, four hundred six".