21787220567 has 16 divisors (see below), whose sum is σ = 24999237120. Its totient is φ = 18600229152.

The previous prime is 21787220551. The next prime is 21787220573. The reversal of 21787220567 is 76502278712.

It is a cyclic number.

It is not a de Polignac number, because 21787220567 - 2⁴ = 21787220551 is a prime.

It is a Smith number, since the sum of its digits (47) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21787220597) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2143784 + ... + 2153922.

It is an arithmetic number, because the mean of its divisors is an integer number (1562452320).

Almost surely, 2^21787220567 is an apocalyptic number.

21787220567 is a deficient number, since it is larger than the sum of its proper divisors (3212016553).

21787220567 is a wasteful number, since it uses less digits than its factorization.

21787220567 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11342.

The product of its (nonzero) digits is 658560, while the sum is 47.

The spelling of 21787220567 in words is "twenty-one billion, seven hundred eighty-seven million, two hundred twenty thousand, five hundred sixty-seven".