28667978 has 4 divisors (see below), whose sum is σ = 43001970. Its totient is φ = 14333988.

The previous prime is 28667953. The next prime is 28668019. The reversal of 28667978 is 87976682.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 87976682 = 2 ⋅43988341.

It can be written as a sum of positive squares in only one way, i.e., 27384289 + 1283689 = 5233^2 + 1133^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7166993 + ... + 7166996.

Almost surely, 2^28667978 is an apocalyptic number.

28667978 is a deficient number, since it is larger than the sum of its proper divisors (14333992).

28667978 is a wasteful number, since it uses less digits than its factorization.

28667978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14333991.

The product of its digits is 2032128, while the sum is 53.

The square root of 28667978 is about 5354.2485934069. The cubic root of 28667978 is about 306.0546771733.

The spelling of 28667978 in words is "twenty-eight million, six hundred sixty-seven thousand, nine hundred seventy-eight".