21768143 has 8 divisors (see below), whose sum is σ = 24051168. Its totient is φ = 19596544.

The previous prime is 21768133. The next prime is 21768179. The reversal of 21768143 is 34186712.

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 21768143 - 2⁴ = 21768127 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 (21768113) 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, 27446 + ... + 28227.

It is an arithmetic number, because the mean of its divisors is an integer number (3006396).

Almost surely, 2^21768143 is an apocalyptic number.

21768143 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

21768143 is a deficient number, since it is larger than the sum of its proper divisors (2283025).

21768143 is a wasteful number, since it uses less digits than its factorization.

21768143 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55713.

The product of its digits is 8064, while the sum is 32.

The square root of 21768143 is about 4665.6342548468. The cubic root of 21768143 is about 279.2161024900.

The spelling of 21768143 in words is "twenty-one million, seven hundred sixty-eight thousand, one hundred forty-three".