28401785 has 4 divisors (see below), whose sum is σ = 34082148. Its totient is φ = 22721424.

The previous prime is 28401767. The next prime is 28401823. The reversal of 28401785 is 58710482.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 58710482 = 2 ⋅29355241.

It can be written as a sum of positive squares in 2 ways, for example, as 3671056 + 24730729 = 1916^2 + 4973^2 .

It is a cyclic number.

It is not a de Polignac number, because 28401785 - 2⁶ = 28401721 is a prime.

It is a super-2 number, since 2×28401785² = 1613322782372450, which contains 22 as substring.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2840174 + ... + 2840183.

It is an arithmetic number, because the mean of its divisors is an integer number (8520537).

Almost surely, 2^28401785 is an apocalyptic number.

It is an amenable number.

28401785 is a deficient number, since it is larger than the sum of its proper divisors (5680363).

28401785 is an equidigital number, since it uses as much as digits as its factorization.

28401785 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5680362.

The product of its (nonzero) digits is 17920, while the sum is 35.

The square root of 28401785 is about 5329.3325097990. The cubic root of 28401785 is about 305.1044522654.

The spelling of 28401785 in words is "twenty-eight million, four hundred one thousand, seven hundred eighty-five".