21248623 has 16 divisors (see below), whose sum is σ = 24710400. Its totient is φ = 18057600.

The previous prime is 21248599. The next prime is 21248639. The reversal of 21248623 is 32684212.

It is a de Polignac number, because none of the positive numbers 2^k-21248623 is a prime.

It is a super-2 number, since 2×21248623² = 903007958792258, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21248591 and 21248600.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21248663) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 36928 + ... + 37498.

It is an arithmetic number, because the mean of its divisors is an integer number (1544400).

Almost surely, 2^21248623 is an apocalyptic number.

21248623 is a deficient number, since it is larger than the sum of its proper divisors (3461777).

21248623 is a wasteful number, since it uses less digits than its factorization.

21248623 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 798.

The product of its digits is 4608, while the sum is 28.

The square root of 21248623 is about 4609.6228696066. The cubic root of 21248623 is about 276.9769298776.

The spelling of 21248623 in words is "twenty-one million, two hundred forty-eight thousand, six hundred twenty-three".