6987661 has 2 divisors, whose sum is σ = 6987662. Its totient is φ = 6987660.

The previous prime is 6987619. The next prime is 6987677. The reversal of 6987661 is 1667896.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 6812100 + 175561 = 2610^2 + 419^2 .

It is a cyclic number.

It is not a de Polignac number, because 6987661 - 2¹⁷ = 6856589 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6987601) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3493830 + 3493831.

It is an arithmetic number, because the mean of its divisors is an integer number (3493831).

Almost surely, 2^6987661 is an apocalyptic number.

It is an amenable number.

6987661 is a deficient number, since it is larger than the sum of its proper divisors (1).

6987661 is an equidigital number, since it uses as much as digits as its factorization.

6987661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 108864, while the sum is 43.

The square root of 6987661 is about 2643.4184307446. The cubic root of 6987661 is about 191.1806537996.

The spelling of 6987661 in words is "six million, nine hundred eighty-seven thousand, six hundred sixty-one".