773721661 has 16 divisors (see below), whose sum is σ = 811819008. Its totient is φ = 736671600.

The previous prime is 773721659. The next prime is 773721673. The reversal of 773721661 is 166127377.

It is a cyclic number.

It is not a de Polignac number, because 773721661 - 2¹ = 773721659 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 (773721691) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 627916 + ... + 629146.

It is an arithmetic number, because the mean of its divisors is an integer number (50738688).

Almost surely, 2^773721661 is an apocalyptic number.

It is an amenable number.

773721661 is a deficient number, since it is larger than the sum of its proper divisors (38097347).

773721661 is a wasteful number, since it uses less digits than its factorization.

773721661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1632.

The product of its digits is 74088, while the sum is 40.

The square root of 773721661 is about 27815.8526923048. The cubic root of 773721661 is about 918.0399595449.

The spelling of 773721661 in words is "seven hundred seventy-three million, seven hundred twenty-one thousand, six hundred sixty-one".