28191242 has 4 divisors (see below), whose sum is σ = 42286866. Its totient is φ = 14095620.

The previous prime is 28191227. The next prime is 28191259. The reversal of 28191242 is 24219182.

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

It can be written as a sum of positive squares in only one way, i.e., 25816561 + 2374681 = 5081^2 + 1541^2 .

It is a super-2 number, since 2×28191242² = 1589492251005128, which contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7047809 + ... + 7047812.

Almost surely, 2^28191242 is an apocalyptic number.

28191242 is a deficient number, since it is larger than the sum of its proper divisors (14095624).

28191242 is a wasteful number, since it uses less digits than its factorization.

28191242 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14095623.

The product of its digits is 2304, while the sum is 29.

The square root of 28191242 is about 5309.5425415002. The cubic root of 28191242 is about 304.3486664910.

The spelling of 28191242 in words is "twenty-eight million, one hundred ninety-one thousand, two hundred forty-two".