221221402 has 8 divisors (see below), whose sum is σ = 332572500. Its totient is φ = 110363904.

The previous prime is 221221397. The next prime is 221221421. The reversal of 221221402 is 204122122.

221221402 is digitally balanced in base 2 and base 3, because in such bases it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 210859441 + 10361961 = 14521^2 + 3219^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 122277 + ... + 124072.

Almost surely, 2^221221402 is an apocalyptic number.

221221402 is a deficient number, since it is larger than the sum of its proper divisors (111351098).

221221402 is a wasteful number, since it uses less digits than its factorization.

221221402 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 246800.

The product of its (nonzero) digits is 128, while the sum is 16.

The square root of 221221402 is about 14873.5134383238. The cubic root of 221221402 is about 604.7961902568.

Adding to 221221402 its reverse (204122122), we get a palindrome (425343524).

The spelling of 221221402 in words is "two hundred twenty-one million, two hundred twenty-one thousand, four hundred two".