20121998 has 16 divisors (see below), whose sum is σ = 33626880. Its totient is φ = 8966496.

The previous prime is 20121989. The next prime is 20122031. The reversal of 20121998 is 89912102.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 12590 + ... + 14097.

It is an arithmetic number, because the mean of its divisors is an integer number (2101680).

Almost surely, 2^20121998 is an apocalyptic number.

20121998 is a deficient number, since it is larger than the sum of its proper divisors (13504882).

20121998 is a wasteful number, since it uses less digits than its factorization.

20121998 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26731.

The product of its (nonzero) digits is 2592, while the sum is 32.

The square root of 20121998 is about 4485.7550089143. The cubic root of 20121998 is about 271.9925657570.

The spelling of 20121998 in words is "twenty million, one hundred twenty-one thousand, nine hundred ninety-eight".