21130623 has 24 divisors (see below), whose sum is σ = 32123520. Its totient is φ = 13366080.

The previous prime is 21130619. The next prime is 21130649. The reversal of 21130623 is 32603112.

21130623 is a `hidden beast` number, since 2 + 11 + 30 + 623 = 666.

It is not a de Polignac number, because 21130623 - 2² = 21130619 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21130596 and 21130605.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21130423) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 14073 + ... + 15501.

It is an arithmetic number, because the mean of its divisors is an integer number (1338480).

Almost surely, 2^21130623 is an apocalyptic number.

21130623 is a deficient number, since it is larger than the sum of its proper divisors (10992897).

21130623 is a wasteful number, since it uses less digits than its factorization.

21130623 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1519 (or 1516 counting only the distinct ones).

The product of its (nonzero) digits is 216, while the sum is 18.

The square root of 21130623 is about 4596.8057387712. The cubic root of 21130623 is about 276.4632657671.

Adding to 21130623 its reverse (32603112), we get a palindrome (53733735).

The spelling of 21130623 in words is "twenty-one million, one hundred thirty thousand, six hundred twenty-three".