28400077 has 4 divisors (see below), whose sum is σ = 29379420. Its totient is φ = 27420736.

The previous prime is 28400069. The next prime is 28400093. The reversal of 28400077 is 77000482.

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 7733961 + 20666116 = 2781^2 + 4546^2 .

It is a cyclic number.

It is not a de Polignac number, because 28400077 - 2³ = 28400069 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 (28400017) 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, 489628 + ... + 489685.

It is an arithmetic number, because the mean of its divisors is an integer number (7344855).

Almost surely, 2^28400077 is an apocalyptic number.

It is an amenable number.

28400077 is a deficient number, since it is larger than the sum of its proper divisors (979343).

28400077 is an equidigital number, since it uses as much as digits as its factorization.

28400077 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 979342.

The product of its (nonzero) digits is 3136, while the sum is 28.

The square root of 28400077 is about 5329.1722621811. The cubic root of 28400077 is about 305.0983361140.

The spelling of 28400077 in words is "twenty-eight million, four hundred thousand, seventy-seven".