2117978 has 16 divisors (see below), whose sum is σ = 3398976. Its totient is φ = 987360.

The previous prime is 2117977. The next prime is 2118007. The reversal of 2117978 is 8797112.

It is not an unprimeable number, because it can be changed into a prime (2117971) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1325 + ... + 2447.

It is an arithmetic number, because the mean of its divisors is an integer number (212436).

2^2117978 is an apocalyptic number.

2117978 is a deficient number, since it is larger than the sum of its proper divisors (1280998).

2117978 is a wasteful number, since it uses less digits than its factorization.

2117978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1189.

The product of its digits is 7056, while the sum is 35.

The square root of 2117978 is about 1455.3274545613. The cubic root of 2117978 is about 128.4223111884.

The spelling of 2117978 in words is "two million, one hundred seventeen thousand, nine hundred seventy-eight".