221212630 has 64 divisors (see below), whose sum is σ = 436363200. Its totient is φ = 80455680.

The previous prime is 221212613. The next prime is 221212633. The reversal of 221212630 is 36212122.

It is a Harshad number since it is a multiple of its sum of digits (19).

It is a junction number, because it is equal to n+sod(n) for n = 221212598 and 221212607.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221212633) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 568476 + ... + 568864.

It is an arithmetic number, because the mean of its divisors is an integer number (6818175).

Almost surely, 2^221212630 is an apocalyptic number.

221212630 is a deficient number, since it is larger than the sum of its proper divisors (215150570).

221212630 is a wasteful number, since it uses less digits than its factorization.

221212630 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 529.

The product of its (nonzero) digits is 288, while the sum is 19.

The square root of 221212630 is about 14873.2185487876. The cubic root of 221212630 is about 604.7881962408.

Adding to 221212630 its reverse (36212122), we get a palindrome (257424752).

It can be divided in two parts, 22 and 1212630, that multiplied together give a triangular number (26677860 = T₇₃₀₄).

The spelling of 221212630 in words is "two hundred twenty-one million, two hundred twelve thousand, six hundred thirty".