2166561063 has 24 divisors (see below), whose sum is σ = 3231697040. Its totient is φ = 1397813760.

The previous prime is 2166561043. The next prime is 2166561079. The reversal of 2166561063 is 3601656612.

It is not a de Polignac number, because 2166561063 - 2⁵ = 2166561031 is a prime.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2166561043) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 16503 + ... + 67863.

Almost surely, 2^2166561063 is an apocalyptic number.

2166561063 is a deficient number, since it is larger than the sum of its proper divisors (1065135977).

2166561063 is a wasteful number, since it uses less digits than its factorization.

2166561063 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51519 (or 51516 counting only the distinct ones).

The product of its (nonzero) digits is 38880, while the sum is 36.

The square root of 2166561063 is about 46546.3324333937. The cubic root of 2166561063 is about 1293.9683226879.

It can be divided in two parts, 21665 and 61063, that added together give a palindrome (82728).

The spelling of 2166561063 in words is "two billion, one hundred sixty-six million, five hundred sixty-one thousand, sixty-three".