6991440 has 40 divisors (see below), whose sum is σ = 21674208. Its totient is φ = 1864320.

The previous prime is 6991427. The next prime is 6991447. The reversal of 6991440 is 441996.

It is a tau number, because it is divible by the number of its divisors (40).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6991447) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 14326 + ... + 14805.

Almost surely, 2^6991440 is an apocalyptic number.

6991440 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

6991440 is an abundant number, since it is smaller than the sum of its proper divisors (14682768).

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

6991440 is a wasteful number, since it uses less digits than its factorization.

6991440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29147 (or 29141 counting only the distinct ones).

The product of its (nonzero) digits is 7776, while the sum is 33.

The square root of 6991440 is about 2644.1331282672. The cubic root of 6991440 is about 191.2151117530.

The spelling of 6991440 in words is "six million, nine hundred ninety-one thousand, four hundred forty".