6939821 has 6 divisors (see below), whose sum is σ = 8072910. Its totient is φ = 5948376.

The previous prime is 6939817. The next prime is 6939827. The reversal of 6939821 is 1289396.

It can be written as a sum of positive squares in only one way, i.e., 6817321 + 122500 = 2611^2 + 350^2 .

It is not a de Polignac number, because 6939821 - 2² = 6939817 is a prime.

It is a super-2 number, since 2×6939821² = 96322231024082, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6939827) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 70766 + ... + 70863.

It is an arithmetic number, because the mean of its divisors is an integer number (1345485).

Almost surely, 2^6939821 is an apocalyptic number.

It is an amenable number.

6939821 is a deficient number, since it is larger than the sum of its proper divisors (1133089).

6939821 is a wasteful number, since it uses less digits than its factorization.

6939821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 141643 (or 141636 counting only the distinct ones).

The product of its digits is 23328, while the sum is 38.

The square root of 6939821 is about 2634.3540005094. The cubic root of 6939821 is about 190.7433575107.

The spelling of 6939821 in words is "six million, nine hundred thirty-nine thousand, eight hundred twenty-one".