28215487 has 4 divisors (see below), whose sum is σ = 29125696. Its totient is φ = 27305280.

The previous prime is 28215479. The next prime is 28215527. The reversal of 28215487 is 78451282.

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

It is a cyclic number.

It is not a de Polignac number, because 28215487 - 2³ = 28215479 is a prime.

It is a super-2 number, since 2×28215487² = 1592227413294338, 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 (28219487) 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, 455058 + ... + 455119.

It is an arithmetic number, because the mean of its divisors is an integer number (7281424).

Almost surely, 2^28215487 is an apocalyptic number.

28215487 is a deficient number, since it is larger than the sum of its proper divisors (910209).

28215487 is an equidigital number, since it uses as much as digits as its factorization.

28215487 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 910208.

The product of its digits is 35840, while the sum is 37.

The square root of 28215487 is about 5311.8252042024. The cubic root of 28215487 is about 304.4358900229.

The spelling of 28215487 in words is "twenty-eight million, two hundred fifteen thousand, four hundred eighty-seven".