28779181 has 16 divisors (see below), whose sum is σ = 31449600. Its totient is φ = 26231040.

The previous prime is 28779173. The next prime is 28779203. The reversal of 28779181 is 18197782.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 28779181 - 2³ = 28779173 is a prime.

It is a super-2 number, since 2×28779181² = 1656482518061522, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28779781) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 144520 + ... + 144718.

It is an arithmetic number, because the mean of its divisors is an integer number (1965600).

Almost surely, 2^28779181 is an apocalyptic number.

It is an amenable number.

28779181 is a deficient number, since it is larger than the sum of its proper divisors (2670419).

28779181 is a wasteful number, since it uses less digits than its factorization.

28779181 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 444.

The product of its digits is 56448, while the sum is 43.

The square root of 28779181 is about 5364.6230995290. The cubic root of 28779181 is about 306.4498949859.

The spelling of 28779181 in words is "twenty-eight million, seven hundred seventy-nine thousand, one hundred eighty-one".