221031516 has 12 divisors (see below), whose sum is σ = 515740232. Its totient is φ = 73677168.

The previous prime is 221031497. The next prime is 221031529. The reversal of 221031516 is 615130122.

221031516 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (12).

It is a junction number, because it is equal to n+sod(n) for n = 221031492 and 221031501.

It is a congruent number.

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, 9209635 + ... + 9209658.

Almost surely, 2^221031516 is an apocalyptic number.

It is an amenable number.

221031516 is an abundant number, since it is smaller than the sum of its proper divisors (294708716).

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

221031516 is a wasteful number, since it uses less digits than its factorization.

221031516 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18419300 (or 18419298 counting only the distinct ones).

The product of its (nonzero) digits is 360, while the sum is 21.

The square root of 221031516 is about 14867.1287073194. The cubic root of 221031516 is about 604.6230978971.

Adding to 221031516 its reverse (615130122), we get a palindrome (836161638).

The spelling of 221031516 in words is "two hundred twenty-one million, thirty-one thousand, five hundred sixteen".