21722143 has 8 divisors (see below), whose sum is σ = 22754016. Its totient is φ = 20697600.

The previous prime is 21722119. The next prime is 21722147. The reversal of 21722143 is 34122712.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21722143 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21722147) 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, 4783 + ... + 8143.

It is an arithmetic number, because the mean of its divisors is an integer number (2844252).

Almost surely, 2^21722143 is an apocalyptic number.

21722143 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

21722143 is a deficient number, since it is larger than the sum of its proper divisors (1031873).

21722143 is a wasteful number, since it uses less digits than its factorization.

21722143 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3665.

The product of its digits is 672, while the sum is 22.

The square root of 21722143 is about 4660.7019857528. The cubic root of 21722143 is about 279.0192858463.

Adding to 21722143 its reverse (34122712), we get a palindrome (55844855).

The spelling of 21722143 in words is "twenty-one million, seven hundred twenty-two thousand, one hundred forty-three".