21388299387 has 16 divisors (see below), whose sum is σ = 35098748160. Its totient is φ = 11281740192.

The previous prime is 21388299367. The next prime is 21388299397. The reversal of 21388299387 is 78399288312.

It is not a de Polignac number, because 21388299387 - 2¹⁸ = 21388037243 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21388299387.

It is not an unprimeable number, because it can be changed into a prime (21388299367) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 39172437 + ... + 39172982.

It is an arithmetic number, because the mean of its divisors is an integer number (2193671760).

Almost surely, 2^21388299387 is an apocalyptic number.

21388299387 is a deficient number, since it is larger than the sum of its proper divisors (13710448773).

21388299387 is a wasteful number, since it uses less digits than its factorization.

21388299387 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 78345442.

The product of its digits is 10450944, while the sum is 60.

The spelling of 21388299387 in words is "twenty-one billion, three hundred eighty-eight million, two hundred ninety-nine thousand, three hundred eighty-seven".