7891840 has 128 divisors (see below), whose sum is σ = 22032000. Its totient is φ = 2672640.

The previous prime is 7891813. The next prime is 7891847. The reversal of 7891840 is 481987.

It is a tau number, because it is divible by the number of its divisors (128).

It is a super-2 number, since 2×7891840² = 124562277171200, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 7891840.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7891847) 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, 133731 + ... + 133789.

It is an arithmetic number, because the mean of its divisors is an integer number (172125).

Almost surely, 2^7891840 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 7891840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (11016000).

7891840 is an abundant number, since it is smaller than the sum of its proper divisors (14140160).

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

7891840 is a wasteful number, since it uses less digits than its factorization.

7891840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 108 (or 96 counting only the distinct ones).

The product of its (nonzero) digits is 16128, while the sum is 37.

The square root of 7891840 is about 2809.2418906175. The cubic root of 7891840 is about 199.0945738698.

The spelling of 7891840 in words is "seven million, eight hundred ninety-one thousand, eight hundred forty".