78712221787 has 4 divisors (see below), whose sum is σ = 79447850136. Its totient is φ = 77976593440.

The previous prime is 78712221761. The next prime is 78712221851.

It is a happy number.

78712221787 is nontrivially palindromic in base 10.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 78712221787 - 2⁷ = 78712221659 is a prime.

It is a super-2 number, since 2×78712221787² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78712221587) 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, 367814014 + ... + 367814227.

It is an arithmetic number, because the mean of its divisors is an integer number (19861962534).

Almost surely, 2^78712221787 is an apocalyptic number.

78712221787 is a deficient number, since it is larger than the sum of its proper divisors (735628349).

78712221787 is a wasteful number, since it uses less digits than its factorization.

78712221787 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 735628348.

The product of its digits is 1229312, while the sum is 52.

The spelling of 78712221787 in words is "seventy-eight billion, seven hundred twelve million, two hundred twenty-one thousand, seven hundred eighty-seven".