21213363661664 has 48 divisors (see below), whose sum is σ = 42041842788960. Its totient is φ = 10536075110400.

The previous prime is 21213363661661. The next prime is 21213363661687. The reversal of 21213363661664 is 46616636331212.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21213363661661) 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, 188357882 + ... + 188470470.

It is an arithmetic number, because the mean of its divisors is an integer number (875871724770).

Almost surely, 2^{21213363661664} is an apocalyptic number.

It is an amenable number.

21213363661664 is a deficient number, since it is larger than the sum of its proper divisors (20828479127296).

21213363661664 is a wasteful number, since it uses less digits than its factorization.

21213363661664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 151743 (or 151735 counting only the distinct ones).

The product of its digits is 3359232, while the sum is 50.

Adding to 21213363661664 its reverse (46616636331212), we get a palindrome (67829999992876).

The spelling of 21213363661664 in words is "twenty-one trillion, two hundred thirteen billion, three hundred sixty-three million, six hundred sixty-one thousand, six hundred sixty-four".