28199971 has 4 divisors (see below), whose sum is σ = 29684200. Its totient is φ = 26715744.

The previous prime is 28199947. The next prime is 28200013. The reversal of 28199971 is 17999182.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 28199971 - 2¹⁷ = 28068899 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28199921) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 742086 + ... + 742123.

It is an arithmetic number, because the mean of its divisors is an integer number (7421050).

Almost surely, 2^28199971 is an apocalyptic number.

28199971 is a deficient number, since it is larger than the sum of its proper divisors (1484229).

28199971 is a wasteful number, since it uses less digits than its factorization.

28199971 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1484228.

The product of its digits is 81648, while the sum is 46.

The square root of 28199971 is about 5310.3644884320. The cubic root of 28199971 is about 304.3800755998.

The spelling of 28199971 in words is "twenty-eight million, one hundred ninety-nine thousand, nine hundred seventy-one".