28667780 has 24 divisors (see below), whose sum is σ = 63744408. Its totient is φ = 10792448.

The previous prime is 28667719. The next prime is 28667801. The reversal of 28667780 is 8776682.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 3104644 + 25563136 = 1762^2 + 5056^2 .

It is a super-2 number, since 2×28667780² = 1643683220256800, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 41819 + ... + 42498.

It is an arithmetic number, because the mean of its divisors is an integer number (2656017).

Almost surely, 2^28667780 is an apocalyptic number.

28667780 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28667780 is an abundant number, since it is smaller than the sum of its proper divisors (35076628).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

28667780 is a wasteful number, since it uses less digits than its factorization.

28667780 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 84343 (or 84341 counting only the distinct ones).

The product of its (nonzero) digits is 225792, while the sum is 44.

The square root of 28667780 is about 5354.2301033855. The cubic root of 28667780 is about 306.0539725664.

The spelling of 28667780 in words is "twenty-eight million, six hundred sixty-seven thousand, seven hundred eighty".