28400561 has 8 divisors (see below), whose sum is σ = 33869184. Its totient is φ = 23284800.

The previous prime is 28400543. The next prime is 28400569. The reversal of 28400561 is 16500482.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a de Polignac number, because none of the positive numbers 2^k-28400561 is a prime.

It is a super-2 number, since 2×28400561² = 1613183730229442, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 28400561.

It is not an unprimeable number, because it can be changed into a prime (28400569) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 88040 + ... + 88361.

It is an arithmetic number, because the mean of its divisors is an integer number (4233648).

Almost surely, 2^28400561 is an apocalyptic number.

It is an amenable number.

28400561 is a deficient number, since it is larger than the sum of its proper divisors (5468623).

28400561 is a wasteful number, since it uses less digits than its factorization.

28400561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 176431.

The product of its (nonzero) digits is 1920, while the sum is 26.

The square root of 28400561 is about 5329.2176724168. The cubic root of 28400561 is about 305.1000692872.

The spelling of 28400561 in words is "twenty-eight million, four hundred thousand, five hundred sixty-one".