665513421 has 8 divisors (see below), whose sum is σ = 904093920. Its totient is φ = 435304272.

The previous prime is 665513419. The next prime is 665513447. The reversal of 665513421 is 124315566.

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

It is not a de Polignac number, because 665513421 - 2¹ = 665513419 is a prime.

It is a super-2 number, since 2×665513421² = 885816227062246482, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665511421) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2092651 + ... + 2092968.

It is an arithmetic number, because the mean of its divisors is an integer number (113011740).

Almost surely, 2^665513421 is an apocalyptic number.

It is an amenable number.

665513421 is a deficient number, since it is larger than the sum of its proper divisors (238580499).

665513421 is a wasteful number, since it uses less digits than its factorization.

665513421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4185675.

The product of its digits is 21600, while the sum is 33.

The square root of 665513421 is about 25797.5468019732. The cubic root of 665513421 is about 873.0764475539.

Adding to 665513421 its reverse (124315566), we get a palindrome (789828987).

The spelling of 665513421 in words is "six hundred sixty-five million, five hundred thirteen thousand, four hundred twenty-one".