645111001 has 4 divisors (see below), whose sum is σ = 653948212. Its totient is φ = 636273792.

The previous prime is 645110989. The next prime is 645111007. The reversal of 645111001 is 100111546.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 100111546 = 2 ⋅50055773.

It can be written as a sum of positive squares in 2 ways, for example, as 147865600 + 497245401 = 12160^2 + 22299^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-645111001 is a prime.

It is a super-2 number, since 2×645111001² = 832336407222444002, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 645111001.

It is not an unprimeable number, because it can be changed into a prime (645111007) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4418496 + ... + 4418641.

It is an arithmetic number, because the mean of its divisors is an integer number (163487053).

Almost surely, 2^645111001 is an apocalyptic number.

It is an amenable number.

645111001 is a deficient number, since it is larger than the sum of its proper divisors (8837211).

645111001 is an equidigital number, since it uses as much as digits as its factorization.

645111001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8837210.

The product of its (nonzero) digits is 120, while the sum is 19.

The square root of 645111001 is about 25399.0354344412. The cubic root of 645111001 is about 864.0618208687.

Adding to 645111001 its reverse (100111546), we get a palindrome (745222547).

The spelling of 645111001 in words is "six hundred forty-five million, one hundred eleven thousand, one".