665827421 has 8 divisors (see below), whose sum is σ = 771663744. Its totient is φ = 562670640.

The previous prime is 665827397. The next prime is 665827429. The reversal of 665827421 is 124728566.

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

It is a de Polignac number, because none of the positive numbers 2^k-665827421 is a prime.

It is a super-2 number, since 2×665827421² = 886652309111022482, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665827429) 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, 669350 + ... + 670343.

It is an arithmetic number, because the mean of its divisors is an integer number (96457968).

Almost surely, 2^665827421 is an apocalyptic number.

It is an amenable number.

665827421 is a deficient number, since it is larger than the sum of its proper divisors (105836323).

665827421 is a wasteful number, since it uses less digits than its factorization.

665827421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1339771.

The product of its digits is 161280, while the sum is 41.

The square root of 665827421 is about 25803.6319342840. The cubic root of 665827421 is about 873.2137364959.

The spelling of 665827421 in words is "six hundred sixty-five million, eight hundred twenty-seven thousand, four hundred twenty-one".