78028513 has 4 divisors (see below), whose sum is σ = 78100740. Its totient is φ = 77956288.

The previous prime is 78028501. The next prime is 78028543. The reversal of 78028513 is 31582087.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 31582087 = 31 ⋅1018777.

It can be written as a sum of positive squares in 2 ways, for example, as 18861649 + 59166864 = 4343^2 + 7692^2 .

It is a cyclic number.

It is not a de Polignac number, because 78028513 - 2¹⁷ = 77897441 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78028543) 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, 34468 + ... + 36661.

It is an arithmetic number, because the mean of its divisors is an integer number (19525185).

Almost surely, 2^78028513 is an apocalyptic number.

It is an amenable number.

78028513 is a deficient number, since it is larger than the sum of its proper divisors (72227).

78028513 is a wasteful number, since it uses less digits than its factorization.

78028513 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 72226.

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

The square root of 78028513 is about 8833.3749495875. The cubic root of 78028513 is about 427.3179243559.

The spelling of 78028513 in words is "seventy-eight million, twenty-eight thousand, five hundred thirteen".