671571521 has 2 divisors, whose sum is σ = 671571522. Its totient is φ = 671571520.

The previous prime is 671571517. The next prime is 671571541. The reversal of 671571521 is 125175176.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 631818496 + 39753025 = 25136^2 + 6305^2 .

It is a cyclic number.

It is not a de Polignac number, because 671571521 - 2² = 671571517 is a prime.

It is not a weakly prime, because it can be changed into another prime (671571541) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 335785760 + 335785761.

It is an arithmetic number, because the mean of its divisors is an integer number (335785761).

Almost surely, 2^671571521 is an apocalyptic number.

It is an amenable number.

671571521 is a deficient number, since it is larger than the sum of its proper divisors (1).

671571521 is an equidigital number, since it uses as much as digits as its factorization.

671571521 is an evil number, because the sum of its binary digits is even.

The product of its digits is 14700, while the sum is 35.

The square root of 671571521 is about 25914.6970076827. The cubic root of 671571521 is about 875.7176245094.

The spelling of 671571521 in words is "six hundred seventy-one million, five hundred seventy-one thousand, five hundred twenty-one".