1256956978 has 4 divisors (see below), whose sum is σ = 1885435470. Its totient is φ = 628478488.

The previous prime is 1256956963. The next prime is 1256956979. The reversal of 1256956978 is 8796596521.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 8796596521 = 449 ⋅19591529.

It can be written as a sum of positive squares in only one way, i.e., 1212641329 + 44315649 = 34823^2 + 6657^2 .

It is a Smith number, since the sum of its digits (58) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (1256956979) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 314239243 + ... + 314239246.

Almost surely, 2^1256956978 is an apocalyptic number.

1256956978 is a deficient number, since it is larger than the sum of its proper divisors (628478492).

1256956978 is an equidigital number, since it uses as much as digits as its factorization.

1256956978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 628478491.

The product of its digits is 8164800, while the sum is 58.

The square root of 1256956978 is about 35453.5890707838. The cubic root of 1256956978 is about 1079.2120962283.

The spelling of 1256956978 in words is "one billion, two hundred fifty-six million, nine hundred fifty-six thousand, nine hundred seventy-eight".