78218823203257 has 4 divisors (see below), whose sum is σ = 85329625312656. Its totient is φ = 71108021093860.

The previous prime is 78218823203239. The next prime is 78218823203303. The reversal of 78218823203257 is 75230232881287.

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 a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-78218823203257 is a prime.

It is a super-2 number, since 2×78218823203257² (a number of 29 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78218823213257) 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, 3555401054683 + ... + 3555401054704.

It is an arithmetic number, because the mean of its divisors is an integer number (21332406328164).

Almost surely, 2^{78218823203257} is an apocalyptic number.

It is an amenable number.

78218823203257 is a deficient number, since it is larger than the sum of its proper divisors (7110802109399).

78218823203257 is a wasteful number, since it uses less digits than its factorization.

78218823203257 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7110802109398.

The product of its (nonzero) digits is 18063360, while the sum is 58.

The spelling of 78218823203257 in words is "seventy-eight trillion, two hundred eighteen billion, eight hundred twenty-three million, two hundred three thousand, two hundred fifty-seven".