28780251 has 16 divisors (see below), whose sum is σ = 38987520. Its totient is φ = 18882720.

The previous prime is 28780249. The next prime is 28780261. The reversal of 28780251 is 15208782.

It is not a de Polignac number, because 28780251 - 2¹ = 28780249 is a prime.

It is not an unprimeable number, because it can be changed into a prime (28780261) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 92386 + ... + 92696.

It is an arithmetic number, because the mean of its divisors is an integer number (2436720).

Almost surely, 2^28780251 is an apocalyptic number.

28780251 is a deficient number, since it is larger than the sum of its proper divisors (10207269).

28780251 is a wasteful number, since it uses less digits than its factorization.

28780251 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 706.

The product of its (nonzero) digits is 8960, while the sum is 33.

The square root of 28780251 is about 5364.7228260181. The cubic root of 28780251 is about 306.4536928392.

The spelling of 28780251 in words is "twenty-eight million, seven hundred eighty thousand, two hundred fifty-one".