3639974333521 has 4 divisors (see below), whose sum is σ = 3677499842212. Its totient is φ = 3602448824832.

The previous prime is 3639974333453. The next prime is 3639974333531. The reversal of 3639974333521 is 1253334799363.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 1894721967121 + 1745252366400 = 1376489^2 + 1321080^2 .

It is a cyclic number.

It is not a de Polignac number, because 3639974333521 - 2³¹ = 3637826849873 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (3639974333531) 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, 18762754200 + ... + 18762754393.

It is an arithmetic number, because the mean of its divisors is an integer number (919374960553).

Almost surely, 2^{3639974333521} is an apocalyptic number.

It is an amenable number.

3639974333521 is a deficient number, since it is larger than the sum of its proper divisors (37525508691).

3639974333521 is an equidigital number, since it uses as much as digits as its factorization.

3639974333521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37525508690.

The product of its digits is 33067440, while the sum is 58.

The spelling of 3639974333521 in words is "three trillion, six hundred thirty-nine billion, nine hundred seventy-four million, three hundred thirty-three thousand, five hundred twenty-one".