2158688491 has 4 divisors (see below), whose sum is σ = 2158802800. Its totient is φ = 2158574184.

The previous prime is 2158688489. The next prime is 2158688527. The reversal of 2158688491 is 1948868512.

It is a happy number.

2158688491 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 2158688491 - 2¹ = 2158688489 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2158638491) 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, 21351 + ... + 69088.

It is an arithmetic number, because the mean of its divisors is an integer number (539700700).

Almost surely, 2^2158688491 is an apocalyptic number.

2158688491 is a deficient number, since it is larger than the sum of its proper divisors (114309).

2158688491 is an equidigital number, since it uses as much as digits as its factorization.

2158688491 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 114308.

The product of its digits is 1105920, while the sum is 52.

The square root of 2158688491 is about 46461.6884217524. The cubic root of 2158688491 is about 1292.3991350790.

The spelling of 2158688491 in words is "two billion, one hundred fifty-eight million, six hundred eighty-eight thousand, four hundred ninety-one".