644305741 has 2 divisors, whose sum is σ = 644305742. Its totient is φ = 644305740.

The previous prime is 644305723. The next prime is 644305747. The reversal of 644305741 is 147503446.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 608855625 + 35450116 = 24675^2 + 5954^2 .

It is a cyclic number.

It is not a de Polignac number, because 644305741 - 2⁵ = 644305709 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 644305697 and 644305706.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (644305747) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322152870 + 322152871.

It is an arithmetic number, because the mean of its divisors is an integer number (322152871).

Almost surely, 2^644305741 is an apocalyptic number.

It is an amenable number.

644305741 is a deficient number, since it is larger than the sum of its proper divisors (1).

644305741 is an equidigital number, since it uses as much as digits as its factorization.

644305741 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 40320, while the sum is 34.

The square root of 644305741 is about 25383.1783076903. The cubic root of 644305741 is about 863.7021493650.

The spelling of 644305741 in words is "six hundred forty-four million, three hundred five thousand, seven hundred forty-one".