645731011 has 2 divisors, whose sum is σ = 645731012. Its totient is φ = 645731010.

The previous prime is 645730991. The next prime is 645731027. The reversal of 645731011 is 110137546.

645731011 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 645731011 - 2¹⁵ = 645698243 is a prime.

It is not a weakly prime, because it can be changed into another prime (645731041) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322865505 + 322865506.

It is an arithmetic number, because the mean of its divisors is an integer number (322865506).

Almost surely, 2^645731011 is an apocalyptic number.

645731011 is a deficient number, since it is larger than the sum of its proper divisors (1).

645731011 is an equidigital number, since it uses as much as digits as its factorization.

645731011 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2520, while the sum is 28.

The square root of 645731011 is about 25411.2378879896. The cubic root of 645731011 is about 864.3385460798.

Adding to 645731011 its reverse (110137546), we get a palindrome (755868557).

The spelling of 645731011 in words is "six hundred forty-five million, seven hundred thirty-one thousand, eleven".