640155428623 has 2 divisors, whose sum is σ = 640155428624. Its totient is φ = 640155428622.

The previous prime is 640155428533. The next prime is 640155428659. The reversal of 640155428623 is 326824551046.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 640155428623 - 2²¹ = 640153331471 is a prime.

It is a super-2 number, since 2×640155428623² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (640155428323) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320077714311 + 320077714312.

It is an arithmetic number, because the mean of its divisors is an integer number (320077714312).

Almost surely, 2^640155428623 is an apocalyptic number.

640155428623 is a deficient number, since it is larger than the sum of its proper divisors (1).

640155428623 is an equidigital number, since it uses as much as digits as its factorization.

640155428623 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1382400, while the sum is 46.

Adding to 640155428623 its reverse (326824551046), we get a palindrome (966979979669).

The spelling of 640155428623 in words is "six hundred forty billion, one hundred fifty-five million, four hundred twenty-eight thousand, six hundred twenty-three".