28011778 has 4 divisors (see below), whose sum is σ = 42017670. Its totient is φ = 14005888.

The previous prime is 28011773. The next prime is 28011793. The reversal of 28011778 is 87711082.

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., 27489049 + 522729 = 5243^2 + 723^2 .

It is not an unprimeable number, because it can be changed into a prime (28011773) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7002943 + ... + 7002946.

Almost surely, 2^28011778 is an apocalyptic number.

28011778 is a deficient number, since it is larger than the sum of its proper divisors (14005892).

28011778 is a wasteful number, since it uses less digits than its factorization.

28011778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14005891.

The product of its (nonzero) digits is 6272, while the sum is 34.

The square root of 28011778 is about 5292.6154215095. The cubic root of 28011778 is about 303.7014685344.

The spelling of 28011778 in words is "twenty-eight million, eleven thousand, seven hundred seventy-eight".