21668857383 has 4 divisors (see below), whose sum is σ = 28891809848. Its totient is φ = 14445904920.

The previous prime is 21668857381. The next prime is 21668857387. The reversal of 21668857383 is 38375886612.

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

It is not a de Polignac number, because 21668857383 - 2¹ = 21668857381 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 (21668857381) 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, 3611476228 + ... + 3611476233.

It is an arithmetic number, because the mean of its divisors is an integer number (7222952462).

Almost surely, 2^21668857383 is an apocalyptic number.

21668857383 is a deficient number, since it is larger than the sum of its proper divisors (7222952465).

21668857383 is an equidigital number, since it uses as much as digits as its factorization.

21668857383 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7222952464.

The product of its digits is 11612160, while the sum is 57.

The spelling of 21668857383 in words is "twenty-one billion, six hundred sixty-eight million, eight hundred fifty-seven thousand, three hundred eighty-three".