21727493 has 2 divisors, whose sum is σ = 21727494. Its totient is φ = 21727492.

The previous prime is 21727487. The next prime is 21727543. The reversal of 21727493 is 39472712.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13786369 + 7941124 = 3713^2 + 2818^2 .

It is a cyclic number.

It is not a de Polignac number, because 21727493 - 2⁴ = 21727477 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 (21727463) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10863746 + 10863747.

It is an arithmetic number, because the mean of its divisors is an integer number (10863747).

Almost surely, 2^21727493 is an apocalyptic number.

It is an amenable number.

21727493 is a deficient number, since it is larger than the sum of its proper divisors (1).

21727493 is an equidigital number, since it uses as much as digits as its factorization.

21727493 is an evil number, because the sum of its binary digits is even.

The product of its digits is 21168, while the sum is 35.

The square root of 21727493 is about 4661.2758982922. The cubic root of 21727493 is about 279.0421907479.

The spelling of 21727493 in words is "twenty-one million, seven hundred twenty-seven thousand, four hundred ninety-three".