2156538566 has 32 divisors (see below), whose sum is σ = 3985728768. Its totient is φ = 852187680.

The previous prime is 2156538563. The next prime is 2156538569. The reversal of 2156538566 is 6658356512.

It is an interprime number because it is at equal distance from previous prime (2156538563) and next prime (2156538569).

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 2156538566.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2156538563) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 170621 + ... + 182823.

It is an arithmetic number, because the mean of its divisors is an integer number (124554024).

Almost surely, 2^2156538566 is an apocalyptic number.

2156538566 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

2156538566 is a deficient number, since it is larger than the sum of its proper divisors (1829190202).

2156538566 is a wasteful number, since it uses less digits than its factorization.

2156538566 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13196.

The product of its digits is 1296000, while the sum is 47.

The square root of 2156538566 is about 46438.5461228062. The cubic root of 2156538566 is about 1291.9699417424.

The spelling of 2156538566 in words is "two billion, one hundred fifty-six million, five hundred thirty-eight thousand, five hundred sixty-six".