28213749 has 12 divisors (see below), whose sum is σ = 40962636. Its totient is φ = 18712512.

The previous prime is 28213747. The next prime is 28213753. The reversal of 28213749 is 94731282.

28213749 is a `hidden beast` number, since 282 + 1 + 374 + 9 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 25826724 + 2387025 = 5082^2 + 1545^2 .

It is not a de Polignac number, because 28213749 - 2¹ = 28213747 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28213747) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 6184 + ... + 9729.

It is an arithmetic number, because the mean of its divisors is an integer number (3413553).

Almost surely, 2^28213749 is an apocalyptic number.

It is an amenable number.

28213749 is a deficient number, since it is larger than the sum of its proper divisors (12748887).

28213749 is a wasteful number, since it uses less digits than its factorization.

28213749 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16116 (or 16113 counting only the distinct ones).

The product of its digits is 24192, while the sum is 36.

The square root of 28213749 is about 5311.6616044323. The cubic root of 28213749 is about 304.4296390771.

The spelling of 28213749 in words is "twenty-eight million, two hundred thirteen thousand, seven hundred forty-nine".