21668022031667 has 16 divisors (see below), whose sum is σ = 24888401262720. Its totient is φ = 18656607816000.

The previous prime is 21668022031619. The next prime is 21668022031679. The reversal of 21668022031667 is 76613022086612.

It is a happy number.

It is not a de Polignac number, because 21668022031667 - 2¹² = 21668022027571 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21668022031067) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 12655898 + ... + 14265615.

It is an arithmetic number, because the mean of its divisors is an integer number (1555525078920).

Almost surely, 2^{21668022031667} is an apocalyptic number.

21668022031667 is a deficient number, since it is larger than the sum of its proper divisors (3220379231053).

21668022031667 is a wasteful number, since it uses less digits than its factorization.

21668022031667 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26925394.

The product of its (nonzero) digits is 1741824, while the sum is 50.

Subtracting 21668022031667 from its reverse (76613022086612), we obtain a palindrome (54945000054945).

The spelling of 21668022031667 in words is "twenty-one trillion, six hundred sixty-eight billion, twenty-two million, thirty-one thousand, six hundred sixty-seven".