21949373 has 2 divisors, whose sum is σ = 21949374. Its totient is φ = 21949372.

The previous prime is 21949331. The next prime is 21949379. The reversal of 21949373 is 37394912.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17530969 + 4418404 = 4187^2 + 2102^2 .

It is a cyclic number.

It is not a de Polignac number, because 21949373 - 2¹² = 21945277 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21949379) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10974686 + 10974687.

It is an arithmetic number, because the mean of its divisors is an integer number (10974687).

Almost surely, 2^21949373 is an apocalyptic number.

It is an amenable number.

21949373 is a deficient number, since it is larger than the sum of its proper divisors (1).

21949373 is an equidigital number, since it uses as much as digits as its factorization.

21949373 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 40824, while the sum is 38.

The square root of 21949373 is about 4685.0157950641. The cubic root of 21949373 is about 279.9888303367.

It can be divided in two parts, 21949 and 373, that added together give a palindrome (22322).

The spelling of 21949373 in words is "twenty-one million, nine hundred forty-nine thousand, three hundred seventy-three".