3987521 has 2 divisors, whose sum is σ = 3987522. Its totient is φ = 3987520.

The previous prime is 3987517. The next prime is 3987523. The reversal of 3987521 is 1257893.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 2676496 + 1311025 = 1636^2 + 1145^2 .

It is a cyclic number.

It is not a de Polignac number, because 3987521 - 2² = 3987517 is a prime.

Together with 3987523, 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 (3987523) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1993760 + 1993761.

It is an arithmetic number, because the mean of its divisors is an integer number (1993761).

Almost surely, 2^3987521 is an apocalyptic number.

It is an amenable number.

3987521 is a deficient number, since it is larger than the sum of its proper divisors (1).

3987521 is an equidigital number, since it uses as much as digits as its factorization.

3987521 is an evil number, because the sum of its binary digits is even.

The product of its digits is 15120, while the sum is 35.

The square root of 3987521 is about 1996.8778129871. The cubic root of 3987521 is about 158.5748567518.

The spelling of 3987521 in words is "three million, nine hundred eighty-seven thousand, five hundred twenty-one".