671622215981 has 2 divisors, whose sum is σ = 671622215982. Its totient is φ = 671622215980.

The previous prime is 671622215933. The next prime is 671622216037. The reversal of 671622215981 is 189512226176.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 378138904900 + 293483311081 = 614930^2 + 541741^2 .

It is a cyclic number.

It is not a de Polignac number, because 671622215981 - 2¹⁰ = 671622214957 is a prime.

It is a super-2 number, since 2×671622215981² (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 (671622275981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 335811107990 + 335811107991.

It is an arithmetic number, because the mean of its divisors is an integer number (335811107991).

Almost surely, 2^671622215981 is an apocalyptic number.

It is an amenable number.

671622215981 is a deficient number, since it is larger than the sum of its proper divisors (1).

671622215981 is an equidigital number, since it uses as much as digits as its factorization.

671622215981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 725760, while the sum is 50.

The spelling of 671622215981 in words is "six hundred seventy-one billion, six hundred twenty-two million, two hundred fifteen thousand, nine hundred eighty-one".