2156555551 has 8 divisors (see below), whose sum is σ = 2219535360. Its totient is φ = 2094456792.

The previous prime is 2156555543. The next prime is 2156555563. The reversal of 2156555551 is 1555556512.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 2156555551 - 2³ = 2156555543 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2156555521) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 215295 + ... + 225088.

It is an arithmetic number, because the mean of its divisors is an integer number (277441920).

Almost surely, 2^2156555551 is an apocalyptic number.

2156555551 is a deficient number, since it is larger than the sum of its proper divisors (62979809).

2156555551 is an equidigital number, since it uses as much as digits as its factorization.

2156555551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 440525.

The product of its digits is 187500, while the sum is 40.

The square root of 2156555551 is about 46438.7289985417. The cubic root of 2156555551 is about 1291.9733336057.

The spelling of 2156555551 in words is "two billion, one hundred fifty-six million, five hundred fifty-five thousand, five hundred fifty-one".