27997778 has 4 divisors (see below), whose sum is σ = 41996670. Its totient is φ = 13998888.

The previous prime is 27997777. The next prime is 27997787. The reversal of 27997778 is 87779972.

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., 25331089 + 2666689 = 5033^2 + 1633^2 .

It is not an unprimeable number, because it can be changed into a prime (27997777) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6999443 + ... + 6999446.

Almost surely, 2^27997778 is an apocalyptic number.

27997778 is a deficient number, since it is larger than the sum of its proper divisors (13998892).

27997778 is a wasteful number, since it uses less digits than its factorization.

27997778 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13998891.

The product of its digits is 3111696, while the sum is 56.

The square root of 27997778 is about 5291.2926586988. The cubic root of 27997778 is about 303.6508644743.

The spelling of 27997778 in words is "twenty-seven million, nine hundred ninety-seven thousand, seven hundred seventy-eight".