21143305544 has 8 divisors (see below), whose sum is σ = 39643697910. Its totient is φ = 10571652768.

The previous prime is 21143305531. The next prime is 21143305577. The reversal of 21143305544 is 44550334112.

It can be written as a sum of positive squares in only one way, i.e., 13771022500 + 7372283044 = 117350^2 + 85862^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is a super-2 number, since 2×21143305544² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21143305544.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1321456589 + ... + 1321456604.

Almost surely, 2^21143305544 is an apocalyptic number.

It is an amenable number.

21143305544 is a deficient number, since it is larger than the sum of its proper divisors (18500392366).

21143305544 is a wasteful number, since it uses less digits than its factorization.

21143305544 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2642913199 (or 2642913195 counting only the distinct ones).

The product of its (nonzero) digits is 28800, while the sum is 32.

Adding to 21143305544 its reverse (44550334112), we get a palindrome (65693639656).

The spelling of 21143305544 in words is "twenty-one billion, one hundred forty-three million, three hundred five thousand, five hundred forty-four".