21563265061 has 4 divisors (see below), whose sum is σ = 23221977772. Its totient is φ = 19904552352.

The previous prime is 21563265047. The next prime is 21563265079. The reversal of 21563265061 is 16056236512.

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

It can be written as a sum of positive squares in 2 ways, for example, as 6854184100 + 14709080961 = 82790^2 + 121281^2 .

It is a cyclic number.

It is not a de Polignac number, because 21563265061 - 2¹¹ = 21563263013 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 21563265061.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21563265011) 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, 829356336 + ... + 829356361.

It is an arithmetic number, because the mean of its divisors is an integer number (5805494443).

Almost surely, 2^21563265061 is an apocalyptic number.

It is an amenable number.

21563265061 is a deficient number, since it is larger than the sum of its proper divisors (1658712711).

21563265061 is a wasteful number, since it uses less digits than its factorization.

21563265061 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1658712710.

The product of its (nonzero) digits is 64800, while the sum is 37.

The spelling of 21563265061 in words is "twenty-one billion, five hundred sixty-three million, two hundred sixty-five thousand, sixty-one".