2178195545 has 4 divisors (see below), whose sum is σ = 2613834660. Its totient is φ = 1742556432.

The previous prime is 2178195541. The next prime is 2178195553. The reversal of 2178195545 is 5455918712.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 578835481 + 1599360064 = 24059^2 + 39992^2 .

It is a cyclic number.

It is not a de Polignac number, because 2178195545 - 2² = 2178195541 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 2178195545.

It is not an unprimeable number, because it can be changed into a prime (2178195541) 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, 217819550 + ... + 217819559.

It is an arithmetic number, because the mean of its divisors is an integer number (653458665).

Almost surely, 2^2178195545 is an apocalyptic number.

It is an amenable number.

2178195545 is a deficient number, since it is larger than the sum of its proper divisors (435639115).

2178195545 is an equidigital number, since it uses as much as digits as its factorization.

2178195545 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 435639114.

The product of its digits is 504000, while the sum is 47.

The square root of 2178195545 is about 46671.1425294046. The cubic root of 2178195545 is about 1296.2804020448.

The spelling of 2178195545 in words is "two billion, one hundred seventy-eight million, one hundred ninety-five thousand, five hundred forty-five".