2126155891 has 4 divisors (see below), whose sum is σ = 2129706000. Its totient is φ = 2122605784.

The previous prime is 2126155877. The next prime is 2126155921. The reversal of 2126155891 is 1985516212.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 2126155891 - 2⁵ = 2126155859 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2126155831) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1774156 + ... + 1775353.

It is an arithmetic number, because the mean of its divisors is an integer number (532426500).

Almost surely, 2^2126155891 is an apocalyptic number.

2126155891 is a deficient number, since it is larger than the sum of its proper divisors (3550109).

2126155891 is an equidigital number, since it uses as much as digits as its factorization.

2126155891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3550108.

The product of its digits is 43200, while the sum is 40.

The square root of 2126155891 is about 46110.2579801935. The cubic root of 2126155891 is about 1285.8738606247.

The spelling of 2126155891 in words is "two billion, one hundred twenty-six million, one hundred fifty-five thousand, eight hundred ninety-one".