2158172775 has 48 divisors (see below), whose sum is σ = 4325080320. Its totient is φ = 1046383200.

The previous prime is 2158172771. The next prime is 2158172789. The reversal of 2158172775 is 5772718512.

It is not a de Polignac number, because 2158172775 - 2² = 2158172771 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 2158172775.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2158172771) 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 47 ways as a sum of consecutive naturals, for example, 137907 + ... + 152756.

It is an arithmetic number, because the mean of its divisors is an integer number (90105840).

Almost surely, 2^2158172775 is an apocalyptic number.

2158172775 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

2158172775 is an abundant number, since it is smaller than the sum of its proper divisors (2166907545).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

2158172775 is a wasteful number, since it uses less digits than its factorization.

2158172775 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 290693 (or 290682 counting only the distinct ones).

The product of its digits is 274400, while the sum is 45.

The square root of 2158172775 is about 46456.1381843132. The cubic root of 2158172775 is about 1292.2962077693.

The spelling of 2158172775 in words is "two billion, one hundred fifty-eight million, one hundred seventy-two thousand, seven hundred seventy-five".