28215718 has 4 divisors (see below), whose sum is σ = 42323580. Its totient is φ = 14107858.

The previous prime is 28215713. The next prime is 28215727. The reversal of 28215718 is 81751282.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 81751282 = 2 ⋅40875641.

It is a super-2 number, since 2×28215718² = 1592253484511048, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28215713) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7053928 + ... + 7053931.

It is an arithmetic number, because the mean of its divisors is an integer number (10580895).

Almost surely, 2^28215718 is an apocalyptic number.

28215718 is a deficient number, since it is larger than the sum of its proper divisors (14107862).

28215718 is a wasteful number, since it uses less digits than its factorization.

28215718 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14107861.

The product of its digits is 8960, while the sum is 34.

The square root of 28215718 is about 5311.8469480963. The cubic root of 28215718 is about 304.4367208255.

The spelling of 28215718 in words is "twenty-eight million, two hundred fifteen thousand, seven hundred eighteen".