78280518661 has 4 divisors (see below), whose sum is σ = 78843688000. Its totient is φ = 77717349324.

The previous prime is 78280518637. The next prime is 78280518691. The reversal of 78280518661 is 16681508287.

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 not a de Polignac number, because 78280518661 - 2³³ = 69690584069 is a prime.

It is a super-2 number, since 2×78280518661² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 78280518599 and 78280518608.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78280518691) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 281584461 + ... + 281584738.

It is an arithmetic number, because the mean of its divisors is an integer number (19710922000).

Almost surely, 2^78280518661 is an apocalyptic number.

It is an amenable number.

78280518661 is a deficient number, since it is larger than the sum of its proper divisors (563169339).

78280518661 is a wasteful number, since it uses less digits than its factorization.

78280518661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 563169338.

The product of its (nonzero) digits is 1290240, while the sum is 52.

The spelling of 78280518661 in words is "seventy-eight billion, two hundred eighty million, five hundred eighteen thousand, six hundred sixty-one".