643165208274551 has 2 divisors, whose sum is σ = 643165208274552. Its totient is φ = 643165208274550.

The previous prime is 643165208274499. The next prime is 643165208274623. The reversal of 643165208274551 is 155472802561346.

643165208274551 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 643165208274551 - 2⁶ = 643165208274487 is a prime.

It is a super-2 number, since 2×643165208274551² (a number of 30 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (643165208274451) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321582604137275 + 321582604137276.

It is an arithmetic number, because the mean of its divisors is an integer number (321582604137276).

Almost surely, 2^{643165208274551} is an apocalyptic number.

643165208274551 is a deficient number, since it is larger than the sum of its proper divisors (1).

643165208274551 is an equidigital number, since it uses as much as digits as its factorization.

643165208274551 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 48384000, while the sum is 59.

The spelling of 643165208274551 in words is "six hundred forty-three trillion, one hundred sixty-five billion, two hundred eight million, two hundred seventy-four thousand, five hundred fifty-one".