671647621 has 2 divisors, whose sum is σ = 671647622. Its totient is φ = 671647620.

The previous prime is 671647601. The next prime is 671647631. The reversal of 671647621 is 126746176.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 671535396 + 112225 = 25914^2 + 335^2 .

It is a cyclic number.

It is not a de Polignac number, because 671647621 - 2⁵ = 671647589 is a prime.

It is a super-2 number, since 2×671647621² = 902221053589919282, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (671647601) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 335823810 + 335823811.

It is an arithmetic number, because the mean of its divisors is an integer number (335823811).

Almost surely, 2^671647621 is an apocalyptic number.

It is an amenable number.

671647621 is a deficient number, since it is larger than the sum of its proper divisors (1).

671647621 is an equidigital number, since it uses as much as digits as its factorization.

671647621 is an evil number, because the sum of its binary digits is even.

The product of its digits is 84672, while the sum is 40.

The square root of 671647621 is about 25916.1652448814. The cubic root of 671647621 is about 875.7507009538.

The spelling of 671647621 in words is "six hundred seventy-one million, six hundred forty-seven thousand, six hundred twenty-one".