2789978 has 4 divisors (see below), whose sum is σ = 4184970. Its totient is φ = 1394988.

The previous prime is 2789951. The next prime is 2789993. The reversal of 2789978 is 8799872.

It is a happy number.

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., 2505889 + 284089 = 1583^2 + 533^2 .

It is a d-powerful number, because it can be written as 2²⁰ + 7⁶ + 8² + 9⁴ + 9⁶ + 7⁷ + 8⁶ .

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 697493 + ... + 697496.

2^2789978 is an apocalyptic number.

2789978 is a deficient number, since it is larger than the sum of its proper divisors (1394992).

2789978 is a wasteful number, since it uses less digits than its factorization.

2789978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1394991.

The product of its digits is 508032, while the sum is 50.

The square root of 2789978 is about 1670.3227233083. The cubic root of 2789978 is about 140.7776116370. Note that the first 3 decimals are identical.

The spelling of 2789978 in words is "two million, seven hundred eighty-nine thousand, nine hundred seventy-eight".