221212531631 has 16 divisors (see below), whose sum is σ = 273430108224. Its totient is φ = 174274101504.

The previous prime is 221212531613. The next prime is 221212531663. The reversal of 221212531631 is 136135212122.

It is a cyclic number.

It is not a de Polignac number, because 221212531631 - 2⁶ = 221212531567 is a prime.

It is a super-2 number, since 2×221212531631² (a number of 23 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 221212531594 and 221212531603.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221212531531) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5195336 + ... + 5237741.

It is an arithmetic number, because the mean of its divisors is an integer number (17089381764).

Almost surely, 2^221212531631 is an apocalyptic number.

221212531631 is a deficient number, since it is larger than the sum of its proper divisors (52217576593).

221212531631 is a wasteful number, since it uses less digits than its factorization.

221212531631 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10433330.

The product of its digits is 4320, while the sum is 29.

Adding to 221212531631 its reverse (136135212122), we get a palindrome (357347743753).

The spelling of 221212531631 in words is "two hundred twenty-one billion, two hundred twelve million, five hundred thirty-one thousand, six hundred thirty-one".