16001440 has 144 divisors (see below), whose sum is σ = 47659752. Its totient is φ = 5031936.

The previous prime is 16001431. The next prime is 16001441. The reversal of 16001440 is 4410061.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 8317456 + 7683984 = 2884^2 + 2772^2 .

It is a Harshad number since it is a multiple of its sum of digits (16).

16001440 is a modest number, since divided by 1440 gives 160 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16001441) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 101842 + ... + 101998.

Almost surely, 2^16001440 is an apocalyptic number.

16001440 is a gapful number since it is divisible by the number (10) 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 16001440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23829876).

16001440 is an abundant number, since it is smaller than the sum of its proper divisors (31658312).

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

16001440 is a wasteful number, since it uses less digits than its factorization.

16001440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 199 (or 184 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 16.

The square root of 16001440 is about 4000.1799959502. The cubic root of 16001440 is about 251.9917692785.

The spelling of 16001440 in words is "sixteen million, one thousand, four hundred forty".