216240640 has 160 divisors (see below), whose sum is σ = 646994304. Its totient is φ = 67338240.

The previous prime is 216240637. The next prime is 216240643. The reversal of 216240640 is 46042612.

It is an interprime number because it is at equal distance from previous prime (216240637) and next prime (216240643).

It is a tau number, because it is divible by the number of its divisors (160).

It is not an unprimeable number, because it can be changed into a prime (216240643) 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, 196572 + ... + 197668.

Almost surely, 2^216240640 is an apocalyptic number.

216240640 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 216240640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (323497152).

216240640 is an abundant number, since it is smaller than the sum of its proper divisors (430753664).

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

216240640 is a wasteful number, since it uses less digits than its factorization.

216240640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1138 (or 1122 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 25.

The square root of 216240640 is about 14705.1229168613. The cubic root of 216240640 is about 600.2227321219. Note that the first 3 decimals are identical.

The spelling of 216240640 in words is "two hundred sixteen million, two hundred forty thousand, six hundred forty".