21512442212 has 12 divisors (see below), whose sum is σ = 37743554940. Its totient is φ = 10728569376.

The previous prime is 21512442167. The next prime is 21512442223. The reversal of 21512442212 is 21224421512.

It can be written as a sum of positive squares in 2 ways, for example, as 4577063716 + 16935378496 = 67654^2 + 130136^2 .

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, 6911183 + ... + 6914294.

It is an arithmetic number, because the mean of its divisors is an integer number (3145296245).

Almost surely, 2^21512442212 is an apocalyptic number.

It is an amenable number.

21512442212 is a deficient number, since it is larger than the sum of its proper divisors (16231112728).

21512442212 is a wasteful number, since it uses less digits than its factorization.

21512442212 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13825870 (or 13825868 counting only the distinct ones).

The product of its digits is 2560, while the sum is 26.

Adding to 21512442212 its reverse (21224421512), we get a palindrome (42736863724).

The spelling of 21512442212 in words is "twenty-one billion, five hundred twelve million, four hundred forty-two thousand, two hundred twelve".