78821222491 has 4 divisors (see below), whose sum is σ = 85986788184. Its totient is φ = 71655656800.

The previous prime is 78821222477. The next prime is 78821222509. The reversal of 78821222491 is 19422212887.

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 78821222491 - 2²⁵ = 78787668059 is a prime.

It is a super-2 number, since 2×78821222491² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (78821222401) 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, 3582782830 + ... + 3582782851.

It is an arithmetic number, because the mean of its divisors is an integer number (21496697046).

Almost surely, 2^78821222491 is an apocalyptic number.

78821222491 is a deficient number, since it is larger than the sum of its proper divisors (7165565693).

78821222491 is a wasteful number, since it uses less digits than its factorization.

78821222491 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7165565692.

The product of its digits is 258048, while the sum is 46.

The spelling of 78821222491 in words is "seventy-eight billion, eight hundred twenty-one million, two hundred twenty-two thousand, four hundred ninety-one".