66464378551 has 4 divisors (see below), whose sum is σ = 66504250872. Its totient is φ = 66424506232.

The previous prime is 66464378473. The next prime is 66464378557. The reversal of 66464378551 is 15587346466.

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 66464378551 - 2³³ = 57874443959 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 66464378492 and 66464378501.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66464378557) 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, 19933660 + ... + 19936993.

It is an arithmetic number, because the mean of its divisors is an integer number (16626062718).

Almost surely, 2^66464378551 is an apocalyptic number.

66464378551 is a deficient number, since it is larger than the sum of its proper divisors (39872321).

66464378551 is a wasteful number, since it uses less digits than its factorization.

66464378551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39872320.

The product of its digits is 14515200, while the sum is 55.

The spelling of 66464378551 in words is "sixty-six billion, four hundred sixty-four million, three hundred seventy-eight thousand, five hundred fifty-one".