20423929 has 2 divisors, whose sum is σ = 20423930. Its totient is φ = 20423928.

The previous prime is 20423927. The next prime is 20423939. The reversal of 20423929 is 92932402.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14288400 + 6135529 = 3780^2 + 2477^2 .

It is a cyclic number.

It is not a de Polignac number, because 20423929 - 2¹ = 20423927 is a prime.

Together with 20423927, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 20423929.

It is not a weakly prime, because it can be changed into another prime (20423927) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10211964 + 10211965.

It is an arithmetic number, because the mean of its divisors is an integer number (10211965).

Almost surely, 2^20423929 is an apocalyptic number.

It is an amenable number.

20423929 is a deficient number, since it is larger than the sum of its proper divisors (1).

20423929 is an equidigital number, since it uses as much as digits as its factorization.

20423929 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 7776, while the sum is 31.

The square root of 20423929 is about 4519.2841247260. The cubic root of 20423929 is about 273.3462355930.

The spelling of 20423929 in words is "twenty million, four hundred twenty-three thousand, nine hundred twenty-nine".