642046642681 has 2 divisors, whose sum is σ = 642046642682. Its totient is φ = 642046642680.

The previous prime is 642046642607. The next prime is 642046642751. The reversal of 642046642681 is 186246640246.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 630580516281 + 11466126400 = 794091^2 + 107080^2 .

It is a cyclic number.

It is not a de Polignac number, because 642046642681 - 2¹⁵ = 642046609913 is a prime.

It is a super-2 number, since 2×642046642681² (a number of 24 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (642046642381) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321023321340 + 321023321341.

It is an arithmetic number, because the mean of its divisors is an integer number (321023321341).

Almost surely, 2^642046642681 is an apocalyptic number.

It is an amenable number.

642046642681 is a deficient number, since it is larger than the sum of its proper divisors (1).

642046642681 is an equidigital number, since it uses as much as digits as its factorization.

642046642681 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2654208, while the sum is 49.

The spelling of 642046642681 in words is "six hundred forty-two billion, forty-six million, six hundred forty-two thousand, six hundred eighty-one".