28721411 has 4 divisors (see below), whose sum is σ = 29970192. Its totient is φ = 27472632.

The previous prime is 28721401. The next prime is 28721437. The reversal of 28721411 is 11412782.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 11412782 = 2 ⋅5706391.

It is a cyclic number.

It is not a de Polignac number, because 28721411 - 2¹⁰ = 28720387 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28721401) 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, 624356 + ... + 624401.

It is an arithmetic number, because the mean of its divisors is an integer number (7492548).

Almost surely, 2^28721411 is an apocalyptic number.

28721411 is a deficient number, since it is larger than the sum of its proper divisors (1248781).

28721411 is a wasteful number, since it uses less digits than its factorization.

28721411 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1248780.

The product of its digits is 896, while the sum is 26.

The square root of 28721411 is about 5359.2360463036. The cubic root of 28721411 is about 306.2447065030.

The spelling of 28721411 in words is "twenty-eight million, seven hundred twenty-one thousand, four hundred eleven".