21429253 has 8 divisors (see below), whose sum is σ = 22226048. Its totient is φ = 20643984.

The previous prime is 21429209. The next prime is 21429257. The reversal of 21429253 is 35292412.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21429253 - 2¹³ = 21421061 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21429257) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1000 + ... + 6622.

It is an arithmetic number, because the mean of its divisors is an integer number (2778256).

Almost surely, 2^21429253 is an apocalyptic number.

It is an amenable number.

21429253 is a deficient number, since it is larger than the sum of its proper divisors (796795).

21429253 is a wasteful number, since it uses less digits than its factorization.

21429253 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5763.

The product of its digits is 4320, while the sum is 28.

The square root of 21429253 is about 4629.1741164056. The cubic root of 21429253 is about 277.7595569500.

The spelling of 21429253 in words is "twenty-one million, four hundred twenty-nine thousand, two hundred fifty-three".