215401440 has 192 divisors, whose sum is σ = 718502400. Its totient is φ = 54134784.

The previous prime is 215401427. The next prime is 215401453. The reversal of 215401440 is 44104512.

It is a happy number.

215401440 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (215401427) and next prime (215401453).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1203271 + ... + 1203449.

It is an arithmetic number, because the mean of its divisors is an integer number (3742200).

Almost surely, 2^215401440 is an apocalyptic number.

215401440 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 215401440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (359251200).

215401440 is an abundant number, since it is smaller than the sum of its proper divisors (503100960).

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

215401440 is a wasteful number, since it uses less digits than its factorization.

215401440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 329 (or 321 counting only the distinct ones).

The product of its (nonzero) digits is 640, while the sum is 21.

The square root of 215401440 is about 14676.5609050622. The cubic root of 215401440 is about 599.4452650511.

Adding to 215401440 its reverse (44104512), we get a palindrome (259505952).

The spelling of 215401440 in words is "two hundred fifteen million, four hundred one thousand, four hundred forty".