665588401 has 3 divisors (see below), whose sum is σ = 665614201. Its totient is φ = 665562602.

The previous prime is 665588393. The next prime is 665588431. The reversal of 665588401 is 104885566.

The square root of 665588401 is 25799.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is not a de Polignac number, because 665588401 - 2³ = 665588393 is a prime.

It is a super-3 number, since 3×665588401³ (a number of 27 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (665588431) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 12900 + ... + 38698.

Almost surely, 2^665588401 is an apocalyptic number.

665588401 is the 25799-th square number.

665588401 is the 12900-th centered octagonal number.

It is an amenable number.

665588401 is a deficient number, since it is larger than the sum of its proper divisors (25800).

665588401 is an frugal number, since it uses more digits than its factorization.

665588401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51598 (or 25799 counting only the distinct ones).

The product of its (nonzero) digits is 230400, while the sum is 43.

The cubic root of 665588401 is about 873.1092346782.

Multiplying 665588401 by its product of nonzero digits (230400), we get a square (153351567590400 = 12383520²).

The spelling of 665588401 in words is "six hundred sixty-five million, five hundred eighty-eight thousand, four hundred one".