2158881921 has 24 divisors (see below), whose sum is σ = 3624279360. Its totient is φ = 1212735456.

The previous prime is 2158881919. The next prime is 2158881929. The reversal of 2158881921 is 1291888512.

It is not a de Polignac number, because 2158881921 - 2¹ = 2158881919 is a prime.

It is a super-2 number, since 2×2158881921² = 9321542297641300482, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (2158881929) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 286690 + ... + 294123.

It is an arithmetic number, because the mean of its divisors is an integer number (151011640).

Almost surely, 2^2158881921 is an apocalyptic number.

2158881921 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

2158881921 is a deficient number, since it is larger than the sum of its proper divisors (1465397439).

2158881921 is a wasteful number, since it uses less digits than its factorization.

2158881921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 580885 (or 580882 counting only the distinct ones).

The product of its digits is 92160, while the sum is 45.

The square root of 2158881921 is about 46463.7699826435. The cubic root of 2158881921 is about 1292.4377358775.

The spelling of 2158881921 in words is "two billion, one hundred fifty-eight million, eight hundred eighty-one thousand, nine hundred twenty-one".