6921240 has 64 divisors (see below), whose sum is σ = 20964960. Its totient is φ = 1827840.

The previous prime is 6921223. The next prime is 6921247. The reversal of 6921240 is 421296.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 6921240.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6921247) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 16230 + ... + 16650.

Almost surely, 2^6921240 is an apocalyptic number.

6921240 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 6921240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (10482480).

6921240 is an abundant number, since it is smaller than the sum of its proper divisors (14043720).

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

6921240 is a wasteful number, since it uses less digits than its factorization.

6921240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 572 (or 568 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 24.

The square root of 6921240 is about 2630.8249656714. The cubic root of 6921240 is about 190.5729703025.

The spelling of 6921240 in words is "six million, nine hundred twenty-one thousand, two hundred forty".