21200429 has 4 divisors (see below), whose sum is σ = 21268476. Its totient is φ = 21132384.

The previous prime is 21200401. The next prime is 21200461. The reversal of 21200429 is 92400212.

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

It can be written as a sum of positive squares in 2 ways, for example, as 4959529 + 16240900 = 2227^2 + 4030^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21200429 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21200429.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21200129) 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, 33554 + ... + 34179.

It is an arithmetic number, because the mean of its divisors is an integer number (5317119).

Almost surely, 2^21200429 is an apocalyptic number.

It is an amenable number.

21200429 is a deficient number, since it is larger than the sum of its proper divisors (68047).

21200429 is an equidigital number, since it uses as much as digits as its factorization.

21200429 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 68046.

The product of its (nonzero) digits is 288, while the sum is 20.

The square root of 21200429 is about 4604.3923594759. The cubic root of 21200429 is about 276.7673675779.

The spelling of 21200429 in words is "twenty-one million, two hundred thousand, four hundred twenty-nine".