2157178111 has 4 divisors (see below), whose sum is σ = 2353285224. Its totient is φ = 1961071000.

The previous prime is 2157178087. The next prime is 2157178117. The reversal of 2157178111 is 1118717512.

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

It is a cyclic number.

It is not a de Polignac number, because 2157178111 - 2¹³ = 2157169919 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 (2157178117) 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, 98053540 + ... + 98053561.

It is an arithmetic number, because the mean of its divisors is an integer number (588321306).

Almost surely, 2^2157178111 is an apocalyptic number.

2157178111 is a deficient number, since it is larger than the sum of its proper divisors (196107113).

2157178111 is a wasteful number, since it uses less digits than its factorization.

2157178111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 196107112.

The product of its digits is 3920, while the sum is 34.

The square root of 2157178111 is about 46445.4315406801. The cubic root of 2157178111 is about 1292.0976450386.

The spelling of 2157178111 in words is "two billion, one hundred fifty-seven million, one hundred seventy-eight thousand, one hundred eleven".