28215669 has 4 divisors (see below), whose sum is σ = 37620896. Its totient is φ = 18810444.

The previous prime is 28215659. The next prime is 28215689. The reversal of 28215669 is 96651282.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 28215669 - 2⁴ = 28215653 is a prime.

It is a super-2 number, since 2×28215669² = 1592247954235122, 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 (28215619) 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, 4702609 + ... + 4702614.

It is an arithmetic number, because the mean of its divisors is an integer number (9405224).

Almost surely, 2^28215669 is an apocalyptic number.

It is an amenable number.

28215669 is a deficient number, since it is larger than the sum of its proper divisors (9405227).

28215669 is an equidigital number, since it uses as much as digits as its factorization.

28215669 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9405226.

The product of its digits is 51840, while the sum is 39.

The square root of 28215669 is about 5311.8423357626. The cubic root of 28215669 is about 304.4365445950.

It can be divided in two parts, 282 and 15669, that added together give a palindrome (15951).

The spelling of 28215669 in words is "twenty-eight million, two hundred fifteen thousand, six hundred sixty-nine".