20408429 has 4 divisors (see below), whose sum is σ = 21295776. Its totient is φ = 19521084.

The previous prime is 20408419. The next prime is 20408459. The reversal of 20408429 is 92480402.

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 20408429 - 2²⁰ = 19359853 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20408419) 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, 443639 + ... + 443684.

It is an arithmetic number, because the mean of its divisors is an integer number (5323944).

Almost surely, 2^20408429 is an apocalyptic number.

It is an amenable number.

20408429 is a deficient number, since it is larger than the sum of its proper divisors (887347).

20408429 is an equidigital number, since it uses as much as digits as its factorization.

20408429 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 887346.

The product of its (nonzero) digits is 4608, while the sum is 29.

The square root of 20408429 is about 4517.5689258715. The cubic root of 20408429 is about 273.2770693565.

The spelling of 20408429 in words is "twenty million, four hundred eight thousand, four hundred twenty-nine".