6721961 has 2 divisors, whose sum is σ = 6721962. Its totient is φ = 6721960.

The previous prime is 6721951. The next prime is 6721969. The reversal of 6721961 is 1691276.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 4177936 + 2544025 = 2044^2 + 1595^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-6721961 is a prime.

It is a super-3 number, since 3×6721961³ (a number of 21 digits) contains 333 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (6721969) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3360980 + 3360981.

It is an arithmetic number, because the mean of its divisors is an integer number (3360981).

Almost surely, 2^6721961 is an apocalyptic number.

It is an amenable number.

6721961 is a deficient number, since it is larger than the sum of its proper divisors (1).

6721961 is an equidigital number, since it uses as much as digits as its factorization.

6721961 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4536, while the sum is 32.

The square root of 6721961 is about 2592.6744878600. The cubic root of 6721961 is about 188.7261133756.

The spelling of 6721961 in words is "six million, seven hundred twenty-one thousand, nine hundred sixty-one".