21232211664 has 80 divisors (see below), whose sum is σ = 55800178560. Its totient is φ = 6955745280.

The previous prime is 21232211633. The next prime is 21232211677. The reversal of 21232211664 is 46611223212.

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 698544 + ... + 728304.

It is an arithmetic number, because the mean of its divisors is an integer number (697502232).

Almost surely, 2^21232211664 is an apocalyptic number.

21232211664 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21232211664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27900089280).

21232211664 is an abundant number, since it is smaller than the sum of its proper divisors (34567966896).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21232211664 is a wasteful number, since it uses less digits than its factorization.

21232211664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30028 (or 30022 counting only the distinct ones).

The product of its digits is 6912, while the sum is 30.

Adding to 21232211664 its reverse (46611223212), we get a palindrome (67843434876).

The spelling of 21232211664 in words is "twenty-one billion, two hundred thirty-two million, two hundred eleven thousand, six hundred sixty-four".