20129990 has 32 divisors (see below), whose sum is σ = 37255680. Its totient is φ = 7828704.

The previous prime is 20129981. The next prime is 20129999. The reversal of 20129990 is 9992102.

It is an interprime number because it is at equal distance from previous prime (20129981) and next prime (20129999).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20129999) 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 15 ways as a sum of consecutive naturals, for example, 65417 + ... + 65723.

It is an arithmetic number, because the mean of its divisors is an integer number (1164240).

Almost surely, 2^20129990 is an apocalyptic number.

20129990 is a deficient number, since it is larger than the sum of its proper divisors (17125690).

20129990 is a wasteful number, since it uses less digits than its factorization.

20129990 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 476.

The product of its (nonzero) digits is 2916, while the sum is 32.

The square root of 20129990 is about 4486.6457404168. The cubic root of 20129990 is about 272.0285707445.

The spelling of 20129990 in words is "twenty million, one hundred twenty-nine thousand, nine hundred ninety".