28720197 has 48 divisors (see below), whose sum is σ = 47880000. Its totient is φ = 16996320.

The previous prime is 28720189. The next prime is 28720207. The reversal of 28720197 is 79102782.

It is not a de Polignac number, because 28720197 - 2³ = 28720189 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28720127) 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 in 47 ways as a sum of consecutive naturals, for example, 192679 + ... + 192827.

It is an arithmetic number, because the mean of its divisors is an integer number (997500).

Almost surely, 2^28720197 is an apocalyptic number.

28720197 is a gapful number since it is divisible by the number (27) formed by its first and last digit.

It is an amenable number.

28720197 is a deficient number, since it is larger than the sum of its proper divisors (19159803).

28720197 is a wasteful number, since it uses less digits than its factorization.

28720197 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 239 (or 222 counting only the distinct ones).

The product of its (nonzero) digits is 14112, while the sum is 36.

The square root of 28720197 is about 5359.1227826949. The cubic root of 28720197 is about 306.2403916463.

The spelling of 28720197 in words is "twenty-eight million, seven hundred twenty thousand, one hundred ninety-seven".