21168723 has 8 divisors (see below), whose sum is σ = 29885328. Its totient is φ = 13282304.

The previous prime is 21168713. The next prime is 21168767. The reversal of 21168723 is 32786112.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21168723 - 2¹⁸ = 20906579 is a prime.

It is a super-2 number, since 2×21168723² = 896229666901458, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21168703) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 207486 + ... + 207587.

It is an arithmetic number, because the mean of its divisors is an integer number (3735666).

Almost surely, 2^21168723 is an apocalyptic number.

21168723 is a deficient number, since it is larger than the sum of its proper divisors (8716605).

21168723 is a wasteful number, since it uses less digits than its factorization.

21168723 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 415093.

The product of its digits is 4032, while the sum is 30.

The square root of 21168723 is about 4600.9480544775. The cubic root of 21168723 is about 276.6293269070.

The spelling of 21168723 in words is "twenty-one million, one hundred sixty-eight thousand, seven hundred twenty-three".