642826300981 has 2 divisors, whose sum is σ = 642826300982. Its totient is φ = 642826300980.

The previous prime is 642826300969. The next prime is 642826301101. The reversal of 642826300981 is 189003628246.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 640625752881 + 2200548100 = 800391^2 + 46910^2 .

It is a cyclic number.

It is not a de Polignac number, because 642826300981 - 2¹⁵ = 642826268213 is a prime.

It is a super-2 number, since 2×642826300981² (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 (642826300681) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321413150490 + 321413150491.

It is an arithmetic number, because the mean of its divisors is an integer number (321413150491).

Almost surely, 2^642826300981 is an apocalyptic number.

It is an amenable number.

642826300981 is a deficient number, since it is larger than the sum of its proper divisors (1).

642826300981 is an equidigital number, since it uses as much as digits as its factorization.

642826300981 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 995328, while the sum is 49.

The spelling of 642826300981 in words is "six hundred forty-two billion, eight hundred twenty-six million, three hundred thousand, nine hundred eighty-one".