21313373 has 2 divisors, whose sum is σ = 21313374. Its totient is φ = 21313372.

The previous prime is 21313363. The next prime is 21313379. The reversal of 21313373 is 37331312.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18292729 + 3020644 = 4277^2 + 1738^2 .

It is a cyclic number.

It is not a de Polignac number, because 21313373 - 2²⁴ = 4536157 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21313379) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10656686 + 10656687.

It is an arithmetic number, because the mean of its divisors is an integer number (10656687).

Almost surely, 2^21313373 is an apocalyptic number.

It is an amenable number.

21313373 is a deficient number, since it is larger than the sum of its proper divisors (1).

21313373 is an equidigital number, since it uses as much as digits as its factorization.

21313373 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1134, while the sum is 23.

The square root of 21313373 is about 4616.6408783877. The cubic root of 21313373 is about 277.2579844856.

Adding to 21313373 its reverse (37331312), we get a palindrome (58644685).

The spelling of 21313373 in words is "twenty-one million, three hundred thirteen thousand, three hundred seventy-three".