28420511 has 4 divisors (see below), whose sum is σ = 32480592. Its totient is φ = 24360432.

The previous prime is 28420501. The next prime is 28420531. The reversal of 28420511 is 11502482.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28420511 is a prime.

It is a super-2 number, since 2×28420511² = 1615450891002242, 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 (28420501) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2030030 + ... + 2030043.

It is an arithmetic number, because the mean of its divisors is an integer number (8120148).

Almost surely, 2^28420511 is an apocalyptic number.

28420511 is a deficient number, since it is larger than the sum of its proper divisors (4060081).

28420511 is an equidigital number, since it uses as much as digits as its factorization.

28420511 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4060080.

The product of its (nonzero) digits is 640, while the sum is 23.

The square root of 28420511 is about 5331.0891007373. The cubic root of 28420511 is about 305.1714918402.

Adding to 28420511 its reverse (11502482), we get a palindrome (39922993).

The spelling of 28420511 in words is "twenty-eight million, four hundred twenty thousand, five hundred eleven".