20643642429 has 4 divisors (see below), whose sum is σ = 27524856576. Its totient is φ = 13762428284.

The previous prime is 20643642421. The next prime is 20643642451. The reversal of 20643642429 is 92424634602.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 20643642429 - 2³ = 20643642421 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20643642421) 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, 3440607069 + ... + 3440607074.

It is an arithmetic number, because the mean of its divisors is an integer number (6881214144).

Almost surely, 2^20643642429 is an apocalyptic number.

It is an amenable number.

20643642429 is a deficient number, since it is larger than the sum of its proper divisors (6881214147).

20643642429 is an equidigital number, since it uses as much as digits as its factorization.

20643642429 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6881214146.

The product of its (nonzero) digits is 497664, while the sum is 42.

It can be divided in two parts, 206436 and 42429, that added together give a triangular number (248865 = T₇₀₅).

The spelling of 20643642429 in words is "twenty billion, six hundred forty-three million, six hundred forty-two thousand, four hundred twenty-nine".