21383377517 has 4 divisors (see below), whose sum is σ = 21383677980. Its totient is φ = 21383077056.

The previous prime is 21383377481. The next prime is 21383377523. The reversal of 21383377517 is 71577338312.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 1327436356 + 20055941161 = 36434^2 + 141619^2 .

It is a cyclic number.

It is not a de Polignac number, because 21383377517 - 2⁶ = 21383377453 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21383377567) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 23459 + ... + 208127.

It is an arithmetic number, because the mean of its divisors is an integer number (5345919495).

Almost surely, 2^21383377517 is an apocalyptic number.

It is an amenable number.

21383377517 is a deficient number, since it is larger than the sum of its proper divisors (300463).

21383377517 is a wasteful number, since it uses less digits than its factorization.

21383377517 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 300462.

The product of its digits is 740880, while the sum is 47.

The spelling of 21383377517 in words is "twenty-one billion, three hundred eighty-three million, three hundred seventy-seven thousand, five hundred seventeen".