21367493 has 4 divisors (see below), whose sum is σ = 24420000. Its totient is φ = 18314988.

The previous prime is 21367481. The next prime is 21367501. The reversal of 21367493 is 39476312.

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 21367493 - 2⁶ = 21367429 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21367433) 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, 1526243 + ... + 1526256.

It is an arithmetic number, because the mean of its divisors is an integer number (6105000).

Almost surely, 2^21367493 is an apocalyptic number.

It is an amenable number.

21367493 is a deficient number, since it is larger than the sum of its proper divisors (3052507).

21367493 is an equidigital number, since it uses as much as digits as its factorization.

21367493 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3052506.

The product of its digits is 27216, while the sum is 35.

The square root of 21367493 is about 4622.4985667926. The cubic root of 21367493 is about 277.4924619872.

The spelling of 21367493 in words is "twenty-one million, three hundred sixty-seven thousand, four hundred ninety-three".