21102623 has 2 divisors, whose sum is σ = 21102624. Its totient is φ = 21102622.

The previous prime is 21102619. The next prime is 21102643. The reversal of 21102623 is 32620112.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21102623 - 2² = 21102619 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21102643) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10551311 + 10551312.

It is an arithmetic number, because the mean of its divisors is an integer number (10551312).

Almost surely, 2^21102623 is an apocalyptic number.

21102623 is a deficient number, since it is larger than the sum of its proper divisors (1).

21102623 is an equidigital number, since it uses as much as digits as its factorization.

21102623 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 144, while the sum is 17.

The square root of 21102623 is about 4593.7591360453. The cubic root of 21102623 is about 276.3410987881.

Adding to 21102623 its reverse (32620112), we get a palindrome (53722735).

The spelling of 21102623 in words is "twenty-one million, one hundred two thousand, six hundred twenty-three".