646988881601 has 2 divisors, whose sum is σ = 646988881602. Its totient is φ = 646988881600.

The previous prime is 646988881549. The next prime is 646988881603. The reversal of 646988881601 is 106188889646.

646988881601 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 639840010000 + 7148871601 = 799900^2 + 84551^2 .

It is a cyclic number.

It is not a de Polignac number, because 646988881601 - 2¹⁴ = 646988865217 is a prime.

It is a super-2 number, since 2×646988881601² (a number of 24 digits) contains 22 as substring.

Together with 646988881603, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (646988881603) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323494440800 + 323494440801.

It is an arithmetic number, because the mean of its divisors is an integer number (323494440801).

Almost surely, 2^646988881601 is an apocalyptic number.

It is an amenable number.

646988881601 is a deficient number, since it is larger than the sum of its proper divisors (1).

646988881601 is an equidigital number, since it uses as much as digits as its factorization.

646988881601 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 31850496, while the sum is 65.

The spelling of 646988881601 in words is "six hundred forty-six billion, nine hundred eighty-eight million, eight hundred eighty-one thousand, six hundred one".