665433021651 has 8 divisors (see below), whose sum is σ = 887458926480. Its totient is φ = 443514565632.

The previous prime is 665433021637. The next prime is 665433021683. The reversal of 665433021651 is 156120334566.

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

It is not a de Polignac number, because 665433021651 - 2¹⁹ = 665432497363 is a prime.

It is a super-2 number, since 2×665433021651² (a number of 24 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (665433021601) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 26847750 + ... + 26872523.

It is an arithmetic number, because the mean of its divisors is an integer number (110932365810).

Almost surely, 2^665433021651 is an apocalyptic number.

665433021651 is a deficient number, since it is larger than the sum of its proper divisors (222025904829).

665433021651 is a wasteful number, since it uses less digits than its factorization.

665433021651 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53724405.

The product of its (nonzero) digits is 388800, while the sum is 42.

The spelling of 665433021651 in words is "six hundred sixty-five billion, four hundred thirty-three million, twenty-one thousand, six hundred fifty-one".