21253616344 has 8 divisors (see below), whose sum is σ = 39850530660. Its totient is φ = 10626808168.

The previous prime is 21253616311. The next prime is 21253616347. The reversal of 21253616344 is 44361635212.

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

It is a hoax number, since the sum of its digits (37) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21253616347) by changing a digit.

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 as a sum of consecutive naturals, namely, 1328351014 + ... + 1328351029.

Almost surely, 2^21253616344 is an apocalyptic number.

It is an amenable number.

21253616344 is a deficient number, since it is larger than the sum of its proper divisors (18596914316).

21253616344 is a wasteful number, since it uses less digits than its factorization.

21253616344 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2656702049 (or 2656702045 counting only the distinct ones).

The product of its digits is 103680, while the sum is 37.

The spelling of 21253616344 in words is "twenty-one billion, two hundred fifty-three million, six hundred sixteen thousand, three hundred forty-four".