221515238 has 24 divisors (see below), whose sum is σ = 382712592. Its totient is φ = 94196592.

The previous prime is 221515237. The next prime is 221515241. The reversal of 221515238 is 832515122.

221515238 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a self number, because there is not a number n which added to its sum of digits gives 221515238.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221515237) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 799556 + ... + 799832.

It is an arithmetic number, because the mean of its divisors is an integer number (15946358).

Almost surely, 2^221515238 is an apocalyptic number.

221515238 is a deficient number, since it is larger than the sum of its proper divisors (161197354).

221515238 is an equidigital number, since it uses as much as digits as its factorization.

221515238 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 764 (or 525 counting only the distinct ones).

The product of its digits is 4800, while the sum is 29.

The square root of 221515238 is about 14883.3879879549. The cubic root of 221515238 is about 605.0638440923.

The spelling of 221515238 in words is "two hundred twenty-one million, five hundred fifteen thousand, two hundred thirty-eight".