78364509 has 16 divisors (see below), whose sum is σ = 111348288. Its totient is φ = 48851712.

The previous prime is 78364499. The next prime is 78364523. The reversal of 78364509 is 90546387.

It is a happy number.

It is not a de Polignac number, because 78364509 - 2⁵ = 78364477 is a prime.

It is a super-2 number, since 2×78364509² = 12281992541622162, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78364549) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3114 + ... + 12900.

It is an arithmetic number, because the mean of its divisors is an integer number (6959268).

Almost surely, 2^78364509 is an apocalyptic number.

It is an amenable number.

78364509 is a deficient number, since it is larger than the sum of its proper divisors (32983779).

78364509 is a wasteful number, since it uses less digits than its factorization.

78364509 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9964.

The product of its (nonzero) digits is 181440, while the sum is 42.

The square root of 78364509 is about 8852.3730716684. The cubic root of 78364509 is about 427.9303992712.

The spelling of 78364509 in words is "seventy-eight million, three hundred sixty-four thousand, five hundred nine".