28199725 has 12 divisors (see below), whose sum is σ = 36488736. Its totient is φ = 21578480.

The previous prime is 28199723. The next prime is 28199729. The reversal of 28199725 is 52799182.

It is not a de Polignac number, because 28199725 - 2¹ = 28199723 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28199723) 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, 23947 + ... + 25096.

It is an arithmetic number, because the mean of its divisors is an integer number (3040728).

Almost surely, 2^28199725 is an apocalyptic number.

28199725 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

28199725 is a deficient number, since it is larger than the sum of its proper divisors (8289011).

28199725 is a wasteful number, since it uses less digits than its factorization.

28199725 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 49076 (or 49071 counting only the distinct ones).

The product of its digits is 90720, while the sum is 43.

The square root of 28199725 is about 5310.3413261296. The cubic root of 28199725 is about 304.3791905195.

It can be divided in two parts, 2819 and 9725, that added together give a square (12544 = 112²).

The spelling of 28199725 in words is "twenty-eight million, one hundred ninety-nine thousand, seven hundred twenty-five".