643013146921 has 2 divisors, whose sum is σ = 643013146922. Its totient is φ = 643013146920.

The previous prime is 643013146879. The next prime is 643013146969. The reversal of 643013146921 is 129641310346.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 614405145600 + 28608001321 = 783840^2 + 169139^2 .

It is a cyclic number.

It is not a de Polignac number, because 643013146921 - 2⁷ = 643013146793 is a prime.

It is a super-2 number, since 2×643013146921² (a number of 24 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (643013146421) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321506573460 + 321506573461.

It is an arithmetic number, because the mean of its divisors is an integer number (321506573461).

Almost surely, 2^643013146921 is an apocalyptic number.

It is an amenable number.

643013146921 is a deficient number, since it is larger than the sum of its proper divisors (1).

643013146921 is an equidigital number, since it uses as much as digits as its factorization.

643013146921 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 93312, while the sum is 40.

The spelling of 643013146921 in words is "six hundred forty-three billion, thirteen million, one hundred forty-six thousand, nine hundred twenty-one".