77221685 has 4 divisors (see below), whose sum is σ = 92666028. Its totient is φ = 61777344.

The previous prime is 77221673. The next prime is 77221691. The reversal of 77221685 is 58612277.

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

It can be written as a sum of positive squares in 2 ways, for example, as 26399044 + 50822641 = 5138^2 + 7129^2 .

It is a cyclic number.

It is not a de Polignac number, because 77221685 - 2⁶ = 77221621 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7722164 + ... + 7722173.

It is an arithmetic number, because the mean of its divisors is an integer number (23166507).

Almost surely, 2^77221685 is an apocalyptic number.

It is an amenable number.

77221685 is a deficient number, since it is larger than the sum of its proper divisors (15444343).

77221685 is a wasteful number, since it uses less digits than its factorization.

77221685 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15444342.

The product of its digits is 47040, while the sum is 38.

The square root of 77221685 is about 8787.5869839223. The cubic root of 77221685 is about 425.8399719997.

The spelling of 77221685 in words is "seventy-seven million, two hundred twenty-one thousand, six hundred eighty-five".