21616123 has 2 divisors, whose sum is σ = 21616124. Its totient is φ = 21616122.

The previous prime is 21616079. The next prime is 21616139. The reversal of 21616123 is 32161612.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21616123 - 2²¹ = 19518971 is a prime.

It is a super-2 number, since 2×21616123² = 934513547102258, which contains 22 as substring.

It is an alternating number because its digits alternate between even and odd.

It is a junction number, because it is equal to n+sod(n) for n = 21616094 and 21616103.

It is not a weakly prime, because it can be changed into another prime (21616423) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10808061 + 10808062.

It is an arithmetic number, because the mean of its divisors is an integer number (10808062).

Almost surely, 2^21616123 is an apocalyptic number.

21616123 is a deficient number, since it is larger than the sum of its proper divisors (1).

21616123 is an equidigital number, since it uses as much as digits as its factorization.

21616123 is an evil number, because the sum of its binary digits is even.

The product of its digits is 432, while the sum is 22.

The square root of 21616123 is about 4649.3142505105. The cubic root of 21616123 is about 278.5646056874.

Adding to 21616123 its reverse (32161612), we get a palindrome (53777735).

The spelling of 21616123 in words is "twenty-one million, six hundred sixteen thousand, one hundred twenty-three".