6721387 has 2 divisors, whose sum is σ = 6721388. Its totient is φ = 6721386.

The previous prime is 6721381. The next prime is 6721411. The reversal of 6721387 is 7831276.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 6721387 - 2⁷ = 6721259 is a prime.

It is equal to p₄₅₈₈₈₁ and since 6721387 and 458881 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (6721381) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3360693 + 3360694.

It is an arithmetic number, because the mean of its divisors is an integer number (3360694).

Almost surely, 2^6721387 is an apocalyptic number.

6721387 is a deficient number, since it is larger than the sum of its proper divisors (1).

6721387 is an equidigital number, since it uses as much as digits as its factorization.

6721387 is an evil number, because the sum of its binary digits is even.

The product of its digits is 14112, while the sum is 34.

The square root of 6721387 is about 2592.5637889934. The cubic root of 6721387 is about 188.7207413385.

The spelling of 6721387 in words is "six million, seven hundred twenty-one thousand, three hundred eighty-seven".