6981645 has 64 divisors (see below), whose sum is σ = 13685760. Its totient is φ = 2995200.

The previous prime is 6981631. The next prime is 6981659. The reversal of 6981645 is 5461896.

6981645 = 133² + 134² + ... + 285².

It is an interprime number because it is at equal distance from previous prime (6981631) and next prime (6981659).

It is not a de Polignac number, because 6981645 - 2⁵ = 6981613 is a prime.

It is a super-3 number, since 3×6981645³ (a number of 22 digits) contains 333 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 53230 + ... + 53360.

It is an arithmetic number, because the mean of its divisors is an integer number (213840).

Almost surely, 2^6981645 is an apocalyptic number.

It is an amenable number.

6981645 is a deficient number, since it is larger than the sum of its proper divisors (6704115).

6981645 is a wasteful number, since it uses less digits than its factorization.

6981645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 186.

The product of its digits is 51840, while the sum is 39.

The square root of 6981645 is about 2642.2802652255. The cubic root of 6981645 is about 191.1257726293.

It can be divided in two parts, 6981 and 645, that added together give a triangular number (7626 = T₁₂₃).

The spelling of 6981645 in words is "six million, nine hundred eighty-one thousand, six hundred forty-five".