2780978 has 4 divisors (see below), whose sum is σ = 4171470. Its totient is φ = 1390488.

The previous prime is 2780971. The next prime is 2780993. The reversal of 2780978 is 8790872.

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

It can be written as a sum of positive squares in only one way, i.e., 2362369 + 418609 = 1537^2 + 647^2 .

It is not an unprimeable number, because it can be changed into a prime (2780971) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 695243 + ... + 695246.

2^2780978 is an apocalyptic number.

2780978 is a deficient number, since it is larger than the sum of its proper divisors (1390492).

2780978 is a wasteful number, since it uses less digits than its factorization.

2780978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1390491.

The product of its (nonzero) digits is 56448, while the sum is 41.

The square root of 2780978 is about 1667.6264569741. The cubic root of 2780978 is about 140.6260736050.

The spelling of 2780978 in words is "two million, seven hundred eighty thousand, nine hundred seventy-eight".