21123373 has 2 divisors, whose sum is σ = 21123374. Its totient is φ = 21123372.

The previous prime is 21123359. The next prime is 21123391. The reversal of 21123373 is 37332112.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15468489 + 5654884 = 3933^2 + 2378^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21123373 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21123313) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10561686 + 10561687.

It is an arithmetic number, because the mean of its divisors is an integer number (10561687).

Almost surely, 2^21123373 is an apocalyptic number.

It is an amenable number.

21123373 is a deficient number, since it is larger than the sum of its proper divisors (1).

21123373 is an equidigital number, since it uses as much as digits as its factorization.

21123373 is an evil number, because the sum of its binary digits is even.

The product of its digits is 756, while the sum is 22.

The square root of 21123373 is about 4596.0170800379. The cubic root of 21123373 is about 276.4316436050.

Adding to 21123373 its reverse (37332112), we get a palindrome (58455485).

The spelling of 21123373 in words is "twenty-one million, one hundred twenty-three thousand, three hundred seventy-three".