644089811 has 2 divisors, whose sum is σ = 644089812. Its totient is φ = 644089810.

The previous prime is 644089783. The next prime is 644089813. The reversal of 644089811 is 118980446.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 644089811 - 2²⁶ = 576980947 is a prime.

Together with 644089813, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (644089813) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322044905 + 322044906.

It is an arithmetic number, because the mean of its divisors is an integer number (322044906).

Almost surely, 2^644089811 is an apocalyptic number.

644089811 is a deficient number, since it is larger than the sum of its proper divisors (1).

644089811 is an equidigital number, since it uses as much as digits as its factorization.

644089811 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 55296, while the sum is 41.

The square root of 644089811 is about 25378.9245438021. The cubic root of 644089811 is about 863.6056527117.

The spelling of 644089811 in words is "six hundred forty-four million, eighty-nine thousand, eight hundred eleven".