28378501 has 4 divisors (see below), whose sum is σ = 29357100. Its totient is φ = 27399904.

The previous prime is 28378421. The next prime is 28378507. The reversal of 28378501 is 10587382.

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

It can be written as a sum of positive squares in 2 ways, for example, as 8584900 + 19793601 = 2930^2 + 4449^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28378501 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28378507) 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, 489256 + ... + 489313.

It is an arithmetic number, because the mean of its divisors is an integer number (7339275).

Almost surely, 2^28378501 is an apocalyptic number.

It is an amenable number.

28378501 is a deficient number, since it is larger than the sum of its proper divisors (978599).

28378501 is an equidigital number, since it uses as much as digits as its factorization.

28378501 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 978598.

The product of its (nonzero) digits is 13440, while the sum is 34.

The square root of 28378501 is about 5327.1475481725. The cubic root of 28378501 is about 305.0210538185.

The spelling of 28378501 in words is "twenty-eight million, three hundred seventy-eight thousand, five hundred one".