216445440 has 80 divisors (see below), whose sum is σ = 691973568. Its totient is φ = 57716736.

The previous prime is 216445403. The next prime is 216445457. The reversal of 216445440 is 44544612.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 216445398 and 216445407.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6412 + ... + 21771.

Almost surely, 2^216445440 is an apocalyptic number.

216445440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

216445440 is an abundant number, since it is smaller than the sum of its proper divisors (475528128).

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

216445440 is an equidigital number, since it uses as much as digits as its factorization.

216445440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28209 (or 28193 counting only the distinct ones).

The product of its (nonzero) digits is 15360, while the sum is 30.

The square root of 216445440 is about 14712.0848284667. The cubic root of 216445440 is about 600.4121612515.

The spelling of 216445440 in words is "two hundred sixteen million, four hundred forty-five thousand, four hundred forty".