66979781064 has 64 divisors (see below), whose sum is σ = 212634230400. Its totient is φ = 19137079872.

The previous prime is 66979781053. The next prime is 66979781107. The reversal of 66979781064 is 46018797966.

66979781064 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a junction number, because it is equal to n+sod(n) for n = 66979780992 and 66979781010.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 22147887 + ... + 22150910.

It is an arithmetic number, because the mean of its divisors is an integer number (3322409850).

Almost surely, 2^66979781064 is an apocalyptic number.

It is an amenable number.

66979781064 is an abundant number, since it is smaller than the sum of its proper divisors (145654449336).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

66979781064 is a wasteful number, since it uses less digits than its factorization.

66979781064 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44298819 (or 44298809 counting only the distinct ones).

The product of its (nonzero) digits is 27433728, while the sum is 63.

The spelling of 66979781064 in words is "sixty-six billion, nine hundred seventy-nine million, seven hundred eighty-one thousand, sixty-four".