21713023 has 2 divisors, whose sum is σ = 21713024. Its totient is φ = 21713022.

The previous prime is 21713009. The next prime is 21713033. The reversal of 21713023 is 32031712.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21713023 - 2¹³ = 21704831 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21713033) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10856511 + 10856512.

It is an arithmetic number, because the mean of its divisors is an integer number (10856512).

Almost surely, 2^21713023 is an apocalyptic number.

21713023 is a deficient number, since it is larger than the sum of its proper divisors (1).

21713023 is an equidigital number, since it uses as much as digits as its factorization.

21713023 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 252, while the sum is 19.

The square root of 21713023 is about 4659.7234896504. The cubic root of 21713023 is about 278.9802318098.

Adding to 21713023 its reverse (32031712), we get a palindrome (53744735).

The spelling of 21713023 in words is "twenty-one million, seven hundred thirteen thousand, twenty-three".