2811978 has 48 divisors (see below), whose sum is σ = 6702696. Its totient is φ = 846720.

The previous prime is 2811973. The next prime is 2811983. The reversal of 2811978 is 8791182.

It is an interprime number because it is at equal distance from previous prime (2811973) and next prime (2811983).

It can be written as a sum of positive squares in 4 ways, for example, as 1996569 + 815409 = 1413^2 + 903^2 .

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (2811973) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 14176 + ... + 14372.

2^2811978 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 2811978, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3351348).

2811978 is an abundant number, since it is smaller than the sum of its proper divisors (3890718).

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

2811978 is a wasteful number, since it uses less digits than its factorization.

2811978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 279 (or 276 counting only the distinct ones).

The product of its digits is 8064, while the sum is 36.

The square root of 2811978 is about 1676.8953455717. The cubic root of 2811978 is about 141.1466709775.

The spelling of 2811978 in words is "two million, eight hundred eleven thousand, nine hundred seventy-eight".