21710123 has 2 divisors, whose sum is σ = 21710124. Its totient is φ = 21710122.

The previous prime is 21710113. The next prime is 21710131. The reversal of 21710123 is 32101712.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21710123 - 2¹⁰ = 21709099 is a prime.

It is not a weakly prime, because it can be changed into another prime (21710113) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10855061 + 10855062.

It is an arithmetic number, because the mean of its divisors is an integer number (10855062).

Almost surely, 2^21710123 is an apocalyptic number.

21710123 is a deficient number, since it is larger than the sum of its proper divisors (1).

21710123 is an equidigital number, since it uses as much as digits as its factorization.

21710123 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 84, while the sum is 17.

The square root of 21710123 is about 4659.4123019969. The cubic root of 21710123 is about 278.9678110199.

Adding to 21710123 its reverse (32101712), we get a palindrome (53811835).

The spelling of 21710123 in words is "twenty-one million, seven hundred ten thousand, one hundred twenty-three".