21788835679 has 4 divisors (see below), whose sum is σ = 23464899976. Its totient is φ = 20112771384.

The previous prime is 21788835631. The next prime is 21788835707. The reversal of 21788835679 is 97653888712.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21788835679 - 2³³ = 13198901087 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21788835679.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21788839679) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 838032129 + ... + 838032154.

It is an arithmetic number, because the mean of its divisors is an integer number (5866224994).

Almost surely, 2^21788835679 is an apocalyptic number.

21788835679 is a deficient number, since it is larger than the sum of its proper divisors (1676064297).

21788835679 is a wasteful number, since it uses less digits than its factorization.

21788835679 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1676064296.

The product of its digits is 40642560, while the sum is 64.

The spelling of 21788835679 in words is "twenty-one billion, seven hundred eighty-eight million, eight hundred thirty-five thousand, six hundred seventy-nine".