66145257021 has 16 divisors (see below), whose sum is σ = 88401051648. Its totient is φ = 43993206000.

The previous prime is 66145257019. The next prime is 66145257047. The reversal of 66145257021 is 12075254166.

66145257021 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 66145257021 - 2¹ = 66145257019 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66145257221) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9567556 + ... + 9574466.

It is an arithmetic number, because the mean of its divisors is an integer number (5525065728).

Almost surely, 2^66145257021 is an apocalyptic number.

It is an amenable number.

66145257021 is a deficient number, since it is larger than the sum of its proper divisors (22255794627).

66145257021 is a wasteful number, since it uses less digits than its factorization.

66145257021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13952.

The product of its (nonzero) digits is 100800, while the sum is 39.

The spelling of 66145257021 in words is "sixty-six billion, one hundred forty-five million, two hundred fifty-seven thousand, twenty-one".