78102211021 has 4 divisors (see below), whose sum is σ = 78110460000. Its totient is φ = 78093962044.

The previous prime is 78102211009. The next prime is 78102211063. The reversal of 78102211021 is 12011220187.

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 a cyclic number.

It is not a de Polignac number, because 78102211021 - 2²¹ = 78100113869 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78102218021) 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, 4110271 + ... + 4129228.

It is an arithmetic number, because the mean of its divisors is an integer number (19527615000).

Almost surely, 2^78102211021 is an apocalyptic number.

It is an amenable number.

78102211021 is a deficient number, since it is larger than the sum of its proper divisors (8248979).

78102211021 is an equidigital number, since it uses as much as digits as its factorization.

78102211021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8248978.

The product of its (nonzero) digits is 448, while the sum is 25.

The spelling of 78102211021 in words is "seventy-eight billion, one hundred two million, two hundred eleven thousand, twenty-one".