2158889691 has 16 divisors (see below), whose sum is σ = 3366243584. Its totient is φ = 1204961184.

The previous prime is 2158889683. The next prime is 2158889713. The reversal of 2158889691 is 1969888512.

It is not a de Polignac number, because 2158889691 - 2³ = 2158889683 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2158889671) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1194496 + ... + 1196301.

It is an arithmetic number, because the mean of its divisors is an integer number (210390224).

Almost surely, 2^2158889691 is an apocalyptic number.

2158889691 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

2158889691 is a deficient number, since it is larger than the sum of its proper divisors (1207353893).

2158889691 is a wasteful number, since it uses less digits than its factorization.

2158889691 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2390850.

The product of its digits is 2488320, while the sum is 57.

The square root of 2158889691 is about 46463.8535961020. The cubic root of 2158889691 is about 1292.4392864068.

The spelling of 2158889691 in words is "two billion, one hundred fifty-eight million, eight hundred eighty-nine thousand, six hundred ninety-one".