643775453 has 2 divisors, whose sum is σ = 643775454. Its totient is φ = 643775452.

The previous prime is 643775413. The next prime is 643775507. The reversal of 643775453 is 354577346.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 637714009 + 6061444 = 25253^2 + 2462^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-643775453 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (643775413) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321887726 + 321887727.

It is an arithmetic number, because the mean of its divisors is an integer number (321887727).

Almost surely, 2^643775453 is an apocalyptic number.

It is an amenable number.

643775453 is a deficient number, since it is larger than the sum of its proper divisors (1).

643775453 is an equidigital number, since it uses as much as digits as its factorization.

643775453 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1058400, while the sum is 44.

The square root of 643775453 is about 25372.7304994949. The cubic root of 643775453 is about 863.4651311467.

The spelling of 643775453 in words is "six hundred forty-three million, seven hundred seventy-five thousand, four hundred fifty-three".