21010623 has 16 divisors (see below), whose sum is σ = 29767680. Its totient is φ = 13136256.

The previous prime is 21010609. The next prime is 21010663. The reversal of 21010623 is 32601012.

It is not a de Polignac number, because 21010623 - 2⁹ = 21010111 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21010663) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 18786 + ... + 19872.

It is an arithmetic number, because the mean of its divisors is an integer number (1860480).

Almost surely, 2^21010623 is an apocalyptic number.

21010623 is a deficient number, since it is larger than the sum of its proper divisors (8757057).

21010623 is a wasteful number, since it uses less digits than its factorization.

21010623 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1486.

The product of its (nonzero) digits is 72, while the sum is 15.

The square root of 21010623 is about 4583.7346127366. The cubic root of 21010623 is about 275.9389305127.

Adding to 21010623 its reverse (32601012), we get a palindrome (53611635).

The spelling of 21010623 in words is "twenty-one million, ten thousand, six hundred twenty-three".