2721440 has 48 divisors (see below), whose sum is σ = 6545448. Its totient is φ = 1069056.

The previous prime is 2721437. The next prime is 2721443. The reversal of 2721440 is 441272.

It is an interprime number because it is at equal distance from previous prime (2721437) and next prime (2721443).

It can be written as a sum of positive squares in 4 ways, for example, as 1882384 + 839056 = 1372^2 + 916^2 .

It is a Harshad number since it is a multiple of its sum of digits (20).

It is not an unprimeable number, because it can be changed into a prime (2721443) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11564 + ... + 11796.

2^2721440 is an apocalyptic number.

2721440 is a gapful number since it is divisible by the number (20) 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 2721440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3272724).

2721440 is an abundant number, since it is smaller than the sum of its proper divisors (3824008).

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

2721440 is a wasteful number, since it uses less digits than its factorization.

2721440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 321 (or 313 counting only the distinct ones).

The product of its (nonzero) digits is 448, while the sum is 20.

The square root of 2721440 is about 1649.6787566069. The cubic root of 2721440 is about 139.6152702349.

The spelling of 2721440 in words is "two million, seven hundred twenty-one thousand, four hundred forty".