221531630 has 16 divisors (see below), whose sum is σ = 416094624. Its totient is φ = 84759840.

The previous prime is 221531627. The next prime is 221531669. The reversal of 221531630 is 36135122.

It is a Harshad number since it is a multiple of its sum of digits (23).

It is a junction number, because it is equal to n+sod(n) for n = 221531596 and 221531605.

It is a congruent number.

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, 481361 + ... + 481820.

It is an arithmetic number, because the mean of its divisors is an integer number (26005914).

Almost surely, 2^221531630 is an apocalyptic number.

221531630 is a deficient number, since it is larger than the sum of its proper divisors (194562994).

221531630 is a wasteful number, since it uses less digits than its factorization.

221531630 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 963211.

The product of its (nonzero) digits is 1080, while the sum is 23.

The square root of 221531630 is about 14883.9386588362. The cubic root of 221531630 is about 605.0787685162.

Adding to 221531630 its reverse (36135122), we get a palindrome (257666752).

The spelling of 221531630 in words is "two hundred twenty-one million, five hundred thirty-one thousand, six hundred thirty".