21716023 has 4 divisors (see below), whose sum is σ = 24818320. Its totient is φ = 18613728.

The previous prime is 21716017. The next prime is 21716029. The reversal of 21716023 is 32061712.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (21716017) and next prime (21716029).

It is a de Polignac number, because none of the positive numbers 2^k-21716023 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21715985 and 21716003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21716029) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1551138 + ... + 1551151.

It is an arithmetic number, because the mean of its divisors is an integer number (6204580).

Almost surely, 2^21716023 is an apocalyptic number.

21716023 is a deficient number, since it is larger than the sum of its proper divisors (3102297).

21716023 is an equidigital number, since it uses as much as digits as its factorization.

21716023 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3102296.

The product of its (nonzero) digits is 504, while the sum is 22.

The square root of 21716023 is about 4660.0453860451. The cubic root of 21716023 is about 278.9930797391.

Adding to 21716023 its reverse (32061712), we get a palindrome (53777735).

The spelling of 21716023 in words is "twenty-one million, seven hundred sixteen thousand, twenty-three".