64919399779 has 4 divisors (see below), whose sum is σ = 69913199776. Its totient is φ = 59925599784.

The previous prime is 64919399761. The next prime is 64919399789. The reversal of 64919399779 is 97799391946.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 64919399779 - 2⁷ = 64919399651 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (64919399729) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2496899979 + ... + 2496900004.

It is an arithmetic number, because the mean of its divisors is an integer number (17478299944).

Almost surely, 2^64919399779 is an apocalyptic number.

64919399779 is a deficient number, since it is larger than the sum of its proper divisors (4993799997).

64919399779 is a wasteful number, since it uses less digits than its factorization.

64919399779 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4993799996.

The product of its digits is 208324872, while the sum is 73.

The spelling of 64919399779 in words is "sixty-four billion, nine hundred nineteen million, three hundred ninety-nine thousand, seven hundred seventy-nine".