20129631 has 4 divisors (see below), whose sum is σ = 26839512. Its totient is φ = 13419752.

The previous prime is 20129597. The next prime is 20129639. The reversal of 20129631 is 13692102.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20129631 - 2⁷ = 20129503 is a prime.

It is a super-2 number, since 2×20129631² = 810404088392322, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20129639) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3354936 + ... + 3354941.

It is an arithmetic number, because the mean of its divisors is an integer number (6709878).

Almost surely, 2^20129631 is an apocalyptic number.

20129631 is a deficient number, since it is larger than the sum of its proper divisors (6709881).

20129631 is an equidigital number, since it uses as much as digits as its factorization.

20129631 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6709880.

The product of its (nonzero) digits is 648, while the sum is 24.

The square root of 20129631 is about 4486.6057326224. The cubic root of 20129631 is about 272.0269536078.

The spelling of 20129631 in words is "twenty million, one hundred twenty-nine thousand, six hundred thirty-one".