78428511 has 24 divisors (see below), whose sum is σ = 129820704. Its totient is φ = 44694720.

The previous prime is 78428509. The next prime is 78428513. The reversal of 78428511 is 11582487.

It is an interprime number because it is at equal distance from previous prime (78428509) and next prime (78428513).

It is not a de Polignac number, because 78428511 - 2¹ = 78428509 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78428513) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 25045 + ... + 28001.

It is an arithmetic number, because the mean of its divisors is an integer number (5409196).

Almost surely, 2^78428511 is an apocalyptic number.

78428511 is a deficient number, since it is larger than the sum of its proper divisors (51392193).

78428511 is a wasteful number, since it uses less digits than its factorization.

78428511 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3391 (or 3388 counting only the distinct ones).

The product of its digits is 17920, while the sum is 36.

The square root of 78428511 is about 8855.9872967389. The cubic root of 78428511 is about 428.0468675931.

The spelling of 78428511 in words is "seventy-eight million, four hundred twenty-eight thousand, five hundred eleven".