66570653721 has 64 divisors (see below), whose sum is σ = 107209992960. Its totient is φ = 36201984000.

The previous prime is 66570653713. The next prime is 66570653767. The reversal of 66570653721 is 12735607566.

It is not a de Polignac number, because 66570653721 - 2³ = 66570653713 is a prime.

It is a super-2 number, since 2×66570653721² (a number of 22 digits) contains 22 as substring.

It is a Smith number, since the sum of its digits (48) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (66570653521) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 4935775 + ... + 4949243.

It is an arithmetic number, because the mean of its divisors is an integer number (1675156140).

Almost surely, 2^66570653721 is an apocalyptic number.

It is an amenable number.

66570653721 is a deficient number, since it is larger than the sum of its proper divisors (40639339239).

66570653721 is a wasteful number, since it uses less digits than its factorization.

66570653721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13818.

The product of its (nonzero) digits is 1587600, while the sum is 48.

The spelling of 66570653721 in words is "sixty-six billion, five hundred seventy million, six hundred fifty-three thousand, seven hundred twenty-one".