21299293 has 4 divisors (see below), whose sum is σ = 21326368. Its totient is φ = 21272220.

The previous prime is 21299281. The next prime is 21299303. The reversal of 21299293 is 39299212.

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 21299293 - 2⁵ = 21299261 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21299273) 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, 12321 + ... + 13942.

It is an arithmetic number, because the mean of its divisors is an integer number (5331592).

Almost surely, 2^21299293 is an apocalyptic number.

It is an amenable number.

21299293 is a deficient number, since it is larger than the sum of its proper divisors (27075).

21299293 is an equidigital number, since it uses as much as digits as its factorization.

21299293 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27074.

The product of its digits is 17496, while the sum is 37.

The square root of 21299293 is about 4615.1157081919. The cubic root of 21299293 is about 277.1969171552.

The spelling of 21299293 in words is "twenty-one million, two hundred ninety-nine thousand, two hundred ninety-three".