2155981193 has 6 divisors (see below), whose sum is σ = 2172265866. Its totient is φ = 2139704592.

The previous prime is 2155981183. The next prime is 2155981237. The reversal of 2155981193 is 3911895512.

It can be written as a sum of positive squares in only one way, i.e., 1904187769 + 251793424 = 43637^2 + 15868^2 .

It is a de Polignac number, because none of the positive numbers 2^k-2155981193 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 (2155981183) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 541496 + ... + 545462.

It is an arithmetic number, because the mean of its divisors is an integer number (362044311).

Almost surely, 2^2155981193 is an apocalyptic number.

It is an amenable number.

2155981193 is a deficient number, since it is larger than the sum of its proper divisors (16284673).

2155981193 is an frugal number, since it uses more digits than its factorization.

2155981193 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8071 (or 4104 counting only the distinct ones).

The product of its digits is 97200, while the sum is 44.

The square root of 2155981193 is about 46432.5445458248. The cubic root of 2155981193 is about 1291.8586258244.

The spelling of 2155981193 in words is "two billion, one hundred fifty-five million, nine hundred eighty-one thousand, one hundred ninety-three".