21303929 has 4 divisors (see below), whose sum is σ = 21341940. Its totient is φ = 21265920.

The previous prime is 21303917. The next prime is 21303943. The reversal of 21303929 is 92930312.

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 7166329 + 14137600 = 2677^2 + 3760^2 .

It is a cyclic number.

It is not a de Polignac number, because 21303929 - 2⁸ = 21303673 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21303979) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 18152 + ... + 19289.

It is an arithmetic number, because the mean of its divisors is an integer number (5335485).

Almost surely, 2^21303929 is an apocalyptic number.

It is an amenable number.

21303929 is a deficient number, since it is larger than the sum of its proper divisors (38011).

21303929 is an equidigital number, since it uses as much as digits as its factorization.

21303929 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38010.

The product of its (nonzero) digits is 2916, while the sum is 29.

The square root of 21303929 is about 4615.6179434611. The cubic root of 21303929 is about 277.2170272387.

It can be divided in two parts, 2130392 and 9, that multiplied together give a triangular number (19173528 = T₆₁₉₂).

The spelling of 21303929 in words is "twenty-one million, three hundred three thousand, nine hundred twenty-nine".