221215402 has 16 divisors (see below), whose sum is σ = 338005152. Its totient is φ = 108555120.

The previous prime is 221215399. The next prime is 221215429. The reversal of 221215402 is 204512122.

It is a self number, because there is not a number n which added to its sum of digits gives 221215402.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 62073 + ... + 65539.

It is an arithmetic number, because the mean of its divisors is an integer number (21125322).

Almost surely, 2^221215402 is an apocalyptic number.

221215402 is a deficient number, since it is larger than the sum of its proper divisors (116789750).

221215402 is a wasteful number, since it uses less digits than its factorization.

221215402 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4053.

The product of its (nonzero) digits is 320, while the sum is 19.

The square root of 221215402 is about 14873.3117361266. The cubic root of 221215402 is about 604.7907224164.

Adding to 221215402 its reverse (204512122), we get a palindrome (425727524).

The spelling of 221215402 in words is "two hundred twenty-one million, two hundred fifteen thousand, four hundred two".