66261475787 has 8 divisors (see below), whose sum is σ = 71363438496. Its totient is φ = 61160216832.

The previous prime is 66261475781. The next prime is 66261475829. The reversal of 66261475787 is 78757416266.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 66261475787 - 2⁴ = 66261475771 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66261475781) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 28418 + ... + 365144.

It is an arithmetic number, because the mean of its divisors is an integer number (8920429812).

Almost surely, 2^66261475787 is an apocalyptic number.

66261475787 is a deficient number, since it is larger than the sum of its proper divisors (5101962709).

66261475787 is a wasteful number, since it uses less digits than its factorization.

66261475787 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 351877.

The product of its digits is 23708160, while the sum is 59.

The spelling of 66261475787 in words is "sixty-six billion, two hundred sixty-one million, four hundred seventy-five thousand, seven hundred eighty-seven".