21385522766 has 16 divisors (see below), whose sum is σ = 32535507168. Its totient is φ = 10540404000.

The previous prime is 21385522747. The next prime is 21385522799. The reversal of 21385522766 is 66722558312.

It is a self number, because there is not a number n which added to its sum of digits gives 21385522766.

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, 1408616 + ... + 1423716.

It is an arithmetic number, because the mean of its divisors is an integer number (2033469198).

Almost surely, 2^21385522766 is an apocalyptic number.

21385522766 is a deficient number, since it is larger than the sum of its proper divisors (11149984402).

21385522766 is a wasteful number, since it uses less digits than its factorization.

21385522766 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25147.

The product of its digits is 1209600, while the sum is 47.

The spelling of 21385522766 in words is "twenty-one billion, three hundred eighty-five million, five hundred twenty-two thousand, seven hundred sixty-six".