2666978 has 4 divisors (see below), whose sum is σ = 4000470. Its totient is φ = 1333488.

The previous prime is 2666969. The next prime is 2666987. The reversal of 2666978 is 8796662.

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

It is an interprime number because it is at equal distance from previous prime (2666969) and next prime (2666987).

It can be written as a sum of positive squares in only one way, i.e., 2666689 + 289 = 1633^2 + 17^2 .

It is a super-2 number, since 2×2666978² = 14225543304968, which contains 22 as substring.

It is a d-powerful number, because it can be written as 2¹¹ + 6⁵ + 6⁷ + 6⁷ + 9² + 7² + 8⁷ .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 666743 + ... + 666746.

2^2666978 is an apocalyptic number.

2666978 is a deficient number, since it is larger than the sum of its proper divisors (1333492).

2666978 is a wasteful number, since it uses less digits than its factorization.

2666978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1333491.

The product of its digits is 217728, while the sum is 44.

The square root of 2666978 is about 1633.0884850491. The cubic root of 2666978 is about 138.6776513220.

The spelling of 2666978 in words is "two million, six hundred sixty-six thousand, nine hundred seventy-eight".