78218013 has 4 divisors (see below), whose sum is σ = 104290688. Its totient is φ = 52145340.

The previous prime is 78217999. The next prime is 78218027. The reversal of 78218013 is 31081287.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is an interprime number because it is at equal distance from previous prime (78217999) and next prime (78218027).

It is not a de Polignac number, because 78218013 - 2⁸ = 78217757 is a prime.

It is a super-2 number, since 2×78218013² = 12236115115336338, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78218033) 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, 13036333 + ... + 13036338.

It is an arithmetic number, because the mean of its divisors is an integer number (26072672).

Almost surely, 2^78218013 is an apocalyptic number.

It is an amenable number.

78218013 is a deficient number, since it is larger than the sum of its proper divisors (26072675).

78218013 is a wasteful number, since it uses less digits than its factorization.

78218013 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26072674.

The product of its (nonzero) digits is 2688, while the sum is 30.

The square root of 78218013 is about 8844.0948095325. The cubic root of 78218013 is about 427.6635727114.

The spelling of 78218013 in words is "seventy-eight million, two hundred eighteen thousand, thirteen".