16531440 has 40 divisors (see below), whose sum is σ = 51248208. Its totient is φ = 4408320.

The previous prime is 16531439. The next prime is 16531447. The reversal of 16531440 is 4413561.

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

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

It is a zygodrome in base 2 and base 4.

It is a self number, because there is not a number n which added to its sum of digits gives 16531440.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16531447) 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, 34201 + ... + 34680.

Almost surely, 2^16531440 is an apocalyptic number.

16531440 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

16531440 is an abundant number, since it is smaller than the sum of its proper divisors (34716768).

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

16531440 is a wasteful number, since it uses less digits than its factorization.

16531440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 68897 (or 68891 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 24.

The square root of 16531440 is about 4065.8873570231. The cubic root of 16531440 is about 254.7437641387.

The spelling of 16531440 in words is "sixteen million, five hundred thirty-one thousand, four hundred forty".