645455 has 8 divisors (see below), whose sum is σ = 780192. Its totient is φ = 512608.

The previous prime is 645443. The next prime is 645467. The reversal of 645455 is 554546.

It is an interprime number because it is at equal distance from previous prime (645443) and next prime (645467).

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

It is a cyclic number.

It is not a de Polignac number, because 645455 - 2¹⁰ = 644431 is a prime.

It is a super-2 number, since 2×645455² = 833224314050, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 645455.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 449 + ... + 1221.

It is an arithmetic number, because the mean of its divisors is an integer number (97524).

2⁶⁴⁵⁴⁵⁵ is an apocalyptic number.

645455 is a deficient number, since it is larger than the sum of its proper divisors (134737).

645455 is a wasteful number, since it uses less digits than its factorization.

645455 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 945.

The product of its digits is 12000, while the sum is 29.

The square root of 645455 is about 803.4021408983. The cubic root of 645455 is about 86.4215377691.

Subtracting from 645455 its reverse (554546), we obtain a palindrome (90909).

The spelling of 645455 in words is "six hundred forty-five thousand, four hundred fifty-five".