21737393 has 2 divisors, whose sum is σ = 21737394. Its totient is φ = 21737392.

The previous prime is 21737383. The next prime is 21737459. The reversal of 21737393 is 39373712.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15547249 + 6190144 = 3943^2 + 2488^2 .

It is a cyclic number.

It is not a de Polignac number, because 21737393 - 2⁶ = 21737329 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21737333) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10868696 + 10868697.

It is an arithmetic number, because the mean of its divisors is an integer number (10868697).

Almost surely, 2^21737393 is an apocalyptic number.

It is an amenable number.

21737393 is a deficient number, since it is larger than the sum of its proper divisors (1).

21737393 is an equidigital number, since it uses as much as digits as its factorization.

21737393 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 23814, while the sum is 35.

The square root of 21737393 is about 4662.3377183555. The cubic root of 21737393 is about 279.0845656048.

The spelling of 21737393 in words is "twenty-one million, seven hundred thirty-seven thousand, three hundred ninety-three".