645440311 has 2 divisors, whose sum is σ = 645440312. Its totient is φ = 645440310.

The previous prime is 645440303. The next prime is 645440347. The reversal of 645440311 is 113044546.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 645440311 - 2³ = 645440303 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 645440311.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (645440111) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322720155 + 322720156.

It is an arithmetic number, because the mean of its divisors is an integer number (322720156).

Almost surely, 2^645440311 is an apocalyptic number.

645440311 is a deficient number, since it is larger than the sum of its proper divisors (1).

645440311 is an equidigital number, since it uses as much as digits as its factorization.

645440311 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5760, while the sum is 28.

The square root of 645440311 is about 25405.5173338391. The cubic root of 645440311 is about 864.2088218212.

Adding to 645440311 its reverse (113044546), we get a palindrome (758484857).

The spelling of 645440311 in words is "six hundred forty-five million, four hundred forty thousand, three hundred eleven".