221015840 has 24 divisors (see below), whose sum is σ = 522150300. Its totient is φ = 88406272.

The previous prime is 221015819. The next prime is 221015843. The reversal of 221015840 is 48510122.

It can be written as a sum of positive squares in 2 ways, for example, as 217031824 + 3984016 = 14732^2 + 1996^2 .

It is not an unprimeable number, because it can be changed into a prime (221015843) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 690515 + ... + 690834.

Almost surely, 2^221015840 is an apocalyptic number.

221015840 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

221015840 is an abundant number, since it is smaller than the sum of its proper divisors (301134460).

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

221015840 is a wasteful number, since it uses less digits than its factorization.

221015840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1381364 (or 1381356 counting only the distinct ones).

The product of its (nonzero) digits is 640, while the sum is 23.

The square root of 221015840 is about 14866.6014946255. The cubic root of 221015840 is about 604.6088038635.

Adding to 221015840 its reverse (48510122), we get a palindrome (269525962).

The spelling of 221015840 in words is "two hundred twenty-one million, fifteen thousand, eight hundred forty".