215240440 has 64 divisors (see below), whose sum is σ = 521717760. Its totient is φ = 79685760.

The previous prime is 215240429. The next prime is 215240449. The reversal of 215240440 is 44042512.

It is a happy number.

It is a super-2 number, since 2×215240440² = 92656894022787200, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (215240449) 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, 24747 + ... + 32293.

It is an arithmetic number, because the mean of its divisors is an integer number (8151840).

Almost surely, 2^215240440 is an apocalyptic number.

215240440 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 215240440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (260858880).

215240440 is an abundant number, since it is smaller than the sum of its proper divisors (306477320).

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

215240440 is a wasteful number, since it uses less digits than its factorization.

215240440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7612 (or 7608 counting only the distinct ones).

The product of its (nonzero) digits is 1280, while the sum is 22.

The square root of 215240440 is about 14671.0749435752. The cubic root of 215240440 is about 599.2958777133.

Adding to 215240440 its reverse (44042512), we get a palindrome (259282952).

The spelling of 215240440 in words is "two hundred fifteen million, two hundred forty thousand, four hundred forty".