215121144 has 64 divisors (see below), whose sum is σ = 616746240. Its totient is φ = 61251840.

The previous prime is 215121133. The next prime is 215121161. The reversal of 215121144 is 441121512.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a self number, because there is not a number n which added to its sum of digits gives 215121144.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 50539 + ... + 54629.

It is an arithmetic number, because the mean of its divisors is an integer number (9636660).

Almost surely, 2^215121144 is an apocalyptic number.

215121144 is a gapful number since it is divisible by the number (24) 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 215121144, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (308373120).

215121144 is an abundant number, since it is smaller than the sum of its proper divisors (401625096).

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

215121144 is a wasteful number, since it uses less digits than its factorization.

215121144 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4420 (or 4416 counting only the distinct ones).

The product of its digits is 320, while the sum is 21.

The square root of 215121144 is about 14667.0086929817. The cubic root of 215121144 is about 599.1851382794.

Adding to 215121144 its reverse (441121512), we get a palindrome (656242656).

The spelling of 215121144 in words is "two hundred fifteen million, one hundred twenty-one thousand, one hundred forty-four".