644945011 has 2 divisors, whose sum is σ = 644945012. Its totient is φ = 644945010.

The previous prime is 644944991. The next prime is 644945017. The reversal of 644945011 is 110549446.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 644945011 - 2¹³ = 644936819 is a prime.

It is not a weakly prime, because it can be changed into another prime (644945017) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322472505 + 322472506.

It is an arithmetic number, because the mean of its divisors is an integer number (322472506).

Almost surely, 2^644945011 is an apocalyptic number.

644945011 is a deficient number, since it is larger than the sum of its proper divisors (1).

644945011 is an equidigital number, since it uses as much as digits as its factorization.

644945011 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 17280, while the sum is 34.

The square root of 644945011 is about 25395.7675804454. The cubic root of 644945011 is about 863.9877054971.

The spelling of 644945011 in words is "six hundred forty-four million, nine hundred forty-five thousand, eleven".