2157779 has 4 divisors (see below), whose sum is σ = 2323776. Its totient is φ = 1991784.

The previous prime is 2157769. The next prime is 2157787. The reversal of 2157779 is 9777512.

2157779 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 2157779 - 2⁴ = 2157763 is a prime.

It is not an unprimeable number, because it can be changed into a prime (2157709) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 82979 + ... + 83004.

It is an arithmetic number, because the mean of its divisors is an integer number (580944).

2^2157779 is an apocalyptic number.

2157779 is a deficient number, since it is larger than the sum of its proper divisors (165997).

2157779 is a wasteful number, since it uses less digits than its factorization.

2157779 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 165996.

The product of its digits is 30870, while the sum is 38.

The square root of 2157779 is about 1468.9380517912. The cubic root of 2157779 is about 129.2217606572.

The spelling of 2157779 in words is "two million, one hundred fifty-seven thousand, seven hundred seventy-nine".