66640603251 has 4 divisors (see below), whose sum is σ = 88854137672. Its totient is φ = 44427068832.

The previous prime is 66640603241. The next prime is 66640603277. The reversal of 66640603251 is 15230604666.

66640603251 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is not a de Polignac number, because 66640603251 - 2⁵ = 66640603219 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66640603241) 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, 11106767206 + ... + 11106767211.

It is an arithmetic number, because the mean of its divisors is an integer number (22213534418).

Almost surely, 2^66640603251 is an apocalyptic number.

66640603251 is a deficient number, since it is larger than the sum of its proper divisors (22213534421).

66640603251 is a wasteful number, since it uses less digits than its factorization.

66640603251 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22213534420.

The product of its (nonzero) digits is 155520, while the sum is 39.

The spelling of 66640603251 in words is "sixty-six billion, six hundred forty million, six hundred three thousand, two hundred fifty-one".