6989821 has 2 divisors, whose sum is σ = 6989822. Its totient is φ = 6989820.

The previous prime is 6989819. The next prime is 6989833. The reversal of 6989821 is 1289896.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 4901796 + 2088025 = 2214^2 + 1445^2 .

It is a cyclic number.

It is not a de Polignac number, because 6989821 - 2¹ = 6989819 is a prime.

It is a super-2 number, since 2×6989821² = 97715195224082, which contains 22 as substring.

Together with 6989819, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6989921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3494910 + 3494911.

It is an arithmetic number, because the mean of its divisors is an integer number (3494911).

Almost surely, 2^6989821 is an apocalyptic number.

It is an amenable number.

6989821 is a deficient number, since it is larger than the sum of its proper divisors (1).

6989821 is an equidigital number, since it uses as much as digits as its factorization.

6989821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 62208, while the sum is 43.

The square root of 6989821 is about 2643.8269610548. The cubic root of 6989821 is about 191.2003507898.

The spelling of 6989821 in words is "six million, nine hundred eighty-nine thousand, eight hundred twenty-one".