28742287 has 4 divisors (see below), whose sum is σ = 32848336. Its totient is φ = 24636240.

The previous prime is 28742267. The next prime is 28742293. The reversal of 28742287 is 78224782.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 78224782 = 2 ⋅39112391.

It is a cyclic number.

It is not a de Polignac number, because 28742287 - 2¹⁵ = 28709519 is a prime.

It is a super-2 number, since 2×28742287² = 1652238123980738, 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 (28742227) 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, 2053014 + ... + 2053027.

It is an arithmetic number, because the mean of its divisors is an integer number (8212084).

Almost surely, 2^28742287 is an apocalyptic number.

28742287 is a deficient number, since it is larger than the sum of its proper divisors (4106049).

28742287 is an equidigital number, since it uses as much as digits as its factorization.

28742287 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4106048.

The product of its digits is 100352, while the sum is 40.

The square root of 28742287 is about 5361.1833581776. The cubic root of 28742287 is about 306.3188859618.

The spelling of 28742287 in words is "twenty-eight million, seven hundred forty-two thousand, two hundred eighty-seven".