221242506 has 16 divisors (see below), whose sum is σ = 442743744. Its totient is φ = 73704384.

The previous prime is 221242493. The next prime is 221242523. The reversal of 221242506 is 605242122.

It is a happy number.

It is a super-2 number, since 2×221242506² = 97896492922320072, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1395 + ... + 21081.

It is an arithmetic number, because the mean of its divisors is an integer number (27671484).

Almost surely, 2^221242506 is an apocalyptic number.

221242506 is an abundant number, since it is smaller than the sum of its proper divisors (221501238).

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

221242506 is a wasteful number, since it uses less digits than its factorization.

221242506 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21565.

The product of its (nonzero) digits is 1920, while the sum is 24.

The square root of 221242506 is about 14874.2228704561. Note that the first 3 decimals coincide. The cubic root of 221242506 is about 604.8154216887.

Adding to 221242506 its reverse (605242122), we get a palindrome (826484628).

The spelling of 221242506 in words is "two hundred twenty-one million, two hundred forty-two thousand, five hundred six".