21144090056 has 8 divisors (see below), whose sum is σ = 39645168870. Its totient is φ = 10572045024.

The previous prime is 21144089999. The next prime is 21144090061. The reversal of 21144090056 is 65009044112.

It can be written as a sum of positive squares in only one way, i.e., 17039125156 + 4104964900 = 130534^2 + 64070^2 .

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

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1321505621 + ... + 1321505636.

Almost surely, 2^21144090056 is an apocalyptic number.

It is an amenable number.

21144090056 is a deficient number, since it is larger than the sum of its proper divisors (18501078814).

21144090056 is a wasteful number, since it uses less digits than its factorization.

21144090056 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2643011263 (or 2643011259 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 32.

The spelling of 21144090056 in words is "twenty-one billion, one hundred forty-four million, ninety thousand, fifty-six".