21388713507 has 24 divisors (see below), whose sum is σ = 35319398400. Its totient is φ = 12218298480.

The previous prime is 21388713491. The next prime is 21388713529. The reversal of 21388713507 is 70531788312.

21388713507 is a `hidden beast` number, since 2 + 138 + 8 + 7 + 1 + 3 + 507 = 666.

It is not a de Polignac number, because 21388713507 - 2⁴ = 21388713491 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21388703507) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 156382 + ... + 259292.

It is an arithmetic number, because the mean of its divisors is an integer number (1471641600).

Almost surely, 2^21388713507 is an apocalyptic number.

21388713507 is a deficient number, since it is larger than the sum of its proper divisors (13930684893).

21388713507 is a wasteful number, since it uses less digits than its factorization.

21388713507 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 106223 (or 106220 counting only the distinct ones).

The product of its (nonzero) digits is 282240, while the sum is 45.

The spelling of 21388713507 in words is "twenty-one billion, three hundred eighty-eight million, seven hundred thirteen thousand, five hundred seven".