21429013 has 4 divisors (see below), whose sum is σ = 21833388. Its totient is φ = 21024640.

The previous prime is 21429011. The next prime is 21429041. The reversal of 21429013 is 31092412.

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 5484964 + 15944049 = 2342^2 + 3993^2 .

It is a cyclic number.

It is not a de Polignac number, because 21429013 - 2¹ = 21429011 is a prime.

It is a Smith number, since the sum of its digits (22) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21429011) 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, 202108 + ... + 202213.

It is an arithmetic number, because the mean of its divisors is an integer number (5458347).

Almost surely, 2^21429013 is an apocalyptic number.

It is an amenable number.

21429013 is a deficient number, since it is larger than the sum of its proper divisors (404375).

21429013 is an equidigital number, since it uses as much as digits as its factorization.

21429013 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 404374.

The product of its (nonzero) digits is 432, while the sum is 22.

The square root of 21429013 is about 4629.1481937825. The cubic root of 21429013 is about 277.7585200101.

The spelling of 21429013 in words is "twenty-one million, four hundred twenty-nine thousand, thirteen".