20429999 has 4 divisors (see below), whose sum is σ = 20709936. Its totient is φ = 20150064.

The previous prime is 20429993. The next prime is 20430029. The reversal of 20429999 is 99992402.

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 20429999 - 2²⁰ = 19381423 is a prime.

It is a Duffinian number.

20429999 is a modest number, since divided by 9999 gives 2042 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20429993) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 139859 + ... + 140004.

It is an arithmetic number, because the mean of its divisors is an integer number (5177484).

Almost surely, 2^20429999 is an apocalyptic number.

20429999 is a deficient number, since it is larger than the sum of its proper divisors (279937).

20429999 is an equidigital number, since it uses as much as digits as its factorization.

20429999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 279936.

The product of its (nonzero) digits is 104976, while the sum is 44.

The square root of 20429999 is about 4519.9556413753. The cubic root of 20429999 is about 273.3733124482.

It can be divided in two parts, 204 and 29999, that added together give a palindrome (30203).

The spelling of 20429999 in words is "twenty million, four hundred twenty-nine thousand, nine hundred ninety-nine".