278986978 has 4 divisors (see below), whose sum is σ = 418480470. Its totient is φ = 139493488.

The previous prime is 278986973. The next prime is 278986979. The reversal of 278986978 is 879689872.

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., 155176849 + 123810129 = 12457^2 + 11127^2 .

It is not an unprimeable number, because it can be changed into a prime (278986973) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69746743 + ... + 69746746.

Almost surely, 2^278986978 is an apocalyptic number.

278986978 is a deficient number, since it is larger than the sum of its proper divisors (139493492).

278986978 is a wasteful number, since it uses less digits than its factorization.

278986978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 139493491.

The product of its digits is 24385536, while the sum is 64.

The square root of 278986978 is about 16702.9032805677. The cubic root of 278986978 is about 653.4233414680.

The spelling of 278986978 in words is "two hundred seventy-eight million, nine hundred eighty-six thousand, nine hundred seventy-eight".