645401 has 4 divisors (see below), whose sum is σ = 656400. Its totient is φ = 634404.

The previous prime is 645397. The next prime is 645409. The reversal of 645401 is 104546.

It is a happy number.

645401 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 645401 - 2² = 645397 is a prime.

It is a Duffinian number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 645401.

It is not an unprimeable number, because it can be changed into a prime (645409) 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, 5411 + ... + 5528.

It is an arithmetic number, because the mean of its divisors is an integer number (164100).

2⁶⁴⁵⁴⁰¹ is an apocalyptic number.

It is an amenable number.

645401 is a deficient number, since it is larger than the sum of its proper divisors (10999).

645401 is a wasteful number, since it uses less digits than its factorization.

645401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10998.

The product of its (nonzero) digits is 480, while the sum is 20.

The square root of 645401 is about 803.3685331154. The cubic root of 645401 is about 86.4191276381.

Adding to 645401 its reverse (104546), we get a palindrome (749947).

The spelling of 645401 in words is "six hundred forty-five thousand, four hundred one".