21781367063 has 2 divisors, whose sum is σ = 21781367064. Its totient is φ = 21781367062.

The previous prime is 21781367039. The next prime is 21781367107. The reversal of 21781367063 is 36076318712.

It is an a-pointer prime, because the next prime (21781367107) can be obtained adding 21781367063 to its sum of digits (44).

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21781367063 - 2¹⁰ = 21781366039 is a prime.

It is a super-2 number, since 2×21781367063² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21781367263) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10890683531 + 10890683532.

It is an arithmetic number, because the mean of its divisors is an integer number (10890683532).

Almost surely, 2^21781367063 is an apocalyptic number.

21781367063 is a deficient number, since it is larger than the sum of its proper divisors (1).

21781367063 is an equidigital number, since it uses as much as digits as its factorization.

21781367063 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 254016, while the sum is 44.

The spelling of 21781367063 in words is "twenty-one billion, seven hundred eighty-one million, three hundred sixty-seven thousand, sixty-three".