21770779965 has 16 divisors (see below), whose sum is σ = 37999907136. Its totient is φ = 10555529600.

The previous prime is 21770779957. The next prime is 21770779967. The reversal of 21770779965 is 56997707712.

It is not a de Polignac number, because 21770779965 - 2³ = 21770779957 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21770779899 and 21770779908.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21770779967) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 65971896 + ... + 65972225.

It is an arithmetic number, because the mean of its divisors is an integer number (2374994196).

Almost surely, 2^21770779965 is an apocalyptic number.

It is an amenable number.

21770779965 is a deficient number, since it is larger than the sum of its proper divisors (16229127171).

21770779965 is a wasteful number, since it uses less digits than its factorization.

21770779965 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 131944140.

The product of its (nonzero) digits is 11668860, while the sum is 60.

The spelling of 21770779965 in words is "twenty-one billion, seven hundred seventy million, seven hundred seventy-nine thousand, nine hundred sixty-five".