77814368221 has 8 divisors (see below), whose sum is σ = 80323139160. Its totient is φ = 75326948928.

The previous prime is 77814368173. The next prime is 77814368257. The reversal of 77814368221 is 12286341877.

It can be written as a sum of positive squares in 4 ways, for example, as 40896972900 + 36917395321 = 202230^2 + 192139^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 77814368221 - 2¹¹ = 77814366173 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 (77814368521) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5330506 + ... + 5345083.

It is an arithmetic number, because the mean of its divisors is an integer number (10040392395).

Almost surely, 2^77814368221 is an apocalyptic number.

It is an amenable number.

77814368221 is a deficient number, since it is larger than the sum of its proper divisors (2508770939).

77814368221 is a wasteful number, since it uses less digits than its factorization.

77814368221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10675823.

The product of its digits is 903168, while the sum is 49.

The spelling of 77814368221 in words is "seventy-seven billion, eight hundred fourteen million, three hundred sixty-eight thousand, two hundred twenty-one".