21366023 has 8 divisors (see below), whose sum is σ = 24462720. Its totient is φ = 18280440.

The previous prime is 21366017. The next prime is 21366041. The reversal of 21366023 is 32066312.

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

It is a cyclic number.

It is not a de Polignac number, because 21366023 - 2⁸ = 21365767 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21366023.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21366053) 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, 1868 + ... + 6798.

It is an arithmetic number, because the mean of its divisors is an integer number (3057840).

Almost surely, 2^21366023 is an apocalyptic number.

21366023 is a deficient number, since it is larger than the sum of its proper divisors (3096697).

21366023 is an equidigital number, since it uses as much as digits as its factorization.

21366023 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5557.

The product of its (nonzero) digits is 1296, while the sum is 23.

The square root of 21366023 is about 4622.3395591410. The cubic root of 21366023 is about 277.4860983756.

It can be divided in two parts, 2136 and 6023, that multiplied together give a triangular number (12865128 = T₅₀₇₂).

The spelling of 21366023 in words is "twenty-one million, three hundred sixty-six thousand, twenty-three".