21544237315164 has 12 divisors (see below), whose sum is σ = 50269887068744. Its totient is φ = 7181412438384.

The previous prime is 21544237315163. The next prime is 21544237315193. The reversal of 21544237315164 is 46151373244512.

It is a tau number, because it is divible by the number of its divisors (12).

It is a super-2 number, since 2×21544237315164² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21544237315163) 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, 897676554787 + ... + 897676554810.

Almost surely, 2^{21544237315164} is an apocalyptic number.

It is an amenable number.

21544237315164 is an abundant number, since it is smaller than the sum of its proper divisors (28725649753580).

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

21544237315164 is a wasteful number, since it uses less digits than its factorization.

21544237315164 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1795353109604 (or 1795353109602 counting only the distinct ones).

The product of its digits is 2419200, while the sum is 48.

The spelling of 21544237315164 in words is "twenty-one trillion, five hundred forty-four billion, two hundred thirty-seven million, three hundred fifteen thousand, one hundred sixty-four".