642406007521 has 2 divisors, whose sum is σ = 642406007522. Its totient is φ = 642406007520.

The previous prime is 642406007491. The next prime is 642406007533. The reversal of 642406007521 is 125700604246.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 341102721600 + 301303285921 = 584040^2 + 548911^2 .

It is a cyclic number.

It is not a de Polignac number, because 642406007521 - 2⁷ = 642406007393 is a prime.

It is a super-2 number, since 2×642406007521² (a number of 24 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (642406037521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321203003760 + 321203003761.

It is an arithmetic number, because the mean of its divisors is an integer number (321203003761).

Almost surely, 2^642406007521 is an apocalyptic number.

It is an amenable number.

642406007521 is a deficient number, since it is larger than the sum of its proper divisors (1).

642406007521 is an equidigital number, since it uses as much as digits as its factorization.

642406007521 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 80640, while the sum is 37.

The spelling of 642406007521 in words is "six hundred forty-two billion, four hundred six million, seven thousand, five hundred twenty-one".