28401251 has 4 divisors (see below), whose sum is σ = 29636112. Its totient is φ = 27166392.

The previous prime is 28401229. The next prime is 28401259. The reversal of 28401251 is 15210482.

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 28401251 - 2¹⁸ = 28139107 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (23), and also a Moran number because the ratio is a prime number: 1234837 = 28401251 / (2 + 8 + 4 + 0 + 1 + 2 + 5 + 1).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28401259) 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, 617396 + ... + 617441.

It is an arithmetic number, because the mean of its divisors is an integer number (7409028).

Almost surely, 2^28401251 is an apocalyptic number.

28401251 is a deficient number, since it is larger than the sum of its proper divisors (1234861).

28401251 is a wasteful number, since it uses less digits than its factorization.

28401251 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1234860.

The product of its (nonzero) digits is 640, while the sum is 23.

The square root of 28401251 is about 5329.2824094807. The cubic root of 28401251 is about 305.1025400992.

The spelling of 28401251 in words is "twenty-eight million, four hundred one thousand, two hundred fifty-one".