6991940 has 24 divisors (see below), whose sum is σ = 14887320. Its totient is φ = 2757888.

The previous prime is 6991939. The next prime is 6991951. The reversal of 6991940 is 491996.

It can be written as a sum of positive squares in 4 ways, for example, as 64516 + 6927424 = 254^2 + 2632^2 .

It is an Ulam number.

It is a zygodrome in base 7.

It is a junction number, because it is equal to n+sod(n) for n = 6991894 and 6991903.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 935 + ... + 3854.

It is an arithmetic number, because the mean of its divisors is an integer number (620305).

Almost surely, 2^6991940 is an apocalyptic number.

It is an amenable number.

6991940 is an abundant number, since it is smaller than the sum of its proper divisors (7895380).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

6991940 is a wasteful number, since it uses less digits than its factorization.

6991940 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4871 (or 4869 counting only the distinct ones).

The product of its (nonzero) digits is 17496, while the sum is 38.

The square root of 6991940 is about 2644.2276755227. The cubic root of 6991940 is about 191.2196699592.

The spelling of 6991940 in words is "six million, nine hundred ninety-one thousand, nine hundred forty".