64778266917 has 32 divisors (see below), whose sum is σ = 118114223360. Its totient is φ = 34168754880.

The previous prime is 64778266909. The next prime is 64778266921. The reversal of 64778266917 is 71966287746.

64778266917 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 64778266917 - 2³ = 64778266909 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64778266997) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 13179934 + ... + 13184847.

It is an arithmetic number, because the mean of its divisors is an integer number (3691069480).

Almost surely, 2^64778266917 is an apocalyptic number.

It is an amenable number.

64778266917 is a deficient number, since it is larger than the sum of its proper divisors (53335956443).

64778266917 is a wasteful number, since it uses less digits than its factorization.

64778266917 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26364810 (or 26364804 counting only the distinct ones).

The product of its digits is 42674688, while the sum is 63.

The spelling of 64778266917 in words is "sixty-four billion, seven hundred seventy-eight million, two hundred sixty-six thousand, nine hundred seventeen".