28991242 has 36 divisors (see below), whose sum is σ = 52854390. Its totient is φ = 11877600.

The previous prime is 28991233. The next prime is 28991251. The reversal of 28991242 is 24219982.

It is an interprime number because it is at equal distance from previous prime (28991233) and next prime (28991251).

It can be written as a sum of positive squares in 3 ways, for example, as 27783441 + 1207801 = 5271^2 + 1099^2 .

It is a super-2 number, since 2×28991242² = 1680984225405128, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 286992 + ... + 287092.

Almost surely, 2^28991242 is an apocalyptic number.

28991242 is a deficient number, since it is larger than the sum of its proper divisors (23863148).

28991242 is a wasteful number, since it uses less digits than its factorization.

28991242 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 247 (or 139 counting only the distinct ones).

The product of its digits is 20736, while the sum is 37.

The square root of 28991242 is about 5384.3515858458. The cubic root of 28991242 is about 307.2007514653.

The spelling of 28991242 in words is "twenty-eight million, nine hundred ninety-one thousand, two hundred forty-two".