21388065366 has 16 divisors (see below), whose sum is σ = 42782266800. Its totient is φ = 7128332448.

The previous prime is 21388065353. The next prime is 21388065409. The reversal of 21388065366 is 66356088312.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 209721 + ... + 294548.

It is an arithmetic number, because the mean of its divisors is an integer number (2673891675).

Almost surely, 2^21388065366 is an apocalyptic number.

21388065366 is an abundant number, since it is smaller than the sum of its proper divisors (21394201434).

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

21388065366 is a wasteful number, since it uses less digits than its factorization.

21388065366 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 511343.

The product of its (nonzero) digits is 1244160, while the sum is 48.

The spelling of 21388065366 in words is "twenty-one billion, three hundred eighty-eight million, sixty-five thousand, three hundred sixty-six".