21210212444 has 24 divisors (see below), whose sum is σ = 38420781840. Its totient is φ = 10233284096.

The previous prime is 21210212437. The next prime is 21210212521. The reversal of 21210212444 is 44421201212.

It is a super-2 number, since 2×21210212444² (a number of 21 digits) contains 22 as substring.

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, 142979 + ... + 250725.

It is an arithmetic number, because the mean of its divisors is an integer number (1600865910).

Almost surely, 2^21210212444 is an apocalyptic number.

It is an amenable number.

21210212444 is a deficient number, since it is larger than the sum of its proper divisors (17210569396).

21210212444 is a wasteful number, since it uses less digits than its factorization.

21210212444 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 109477 (or 109475 counting only the distinct ones).

The product of its (nonzero) digits is 1024, while the sum is 23.

Adding to 21210212444 its reverse (44421201212), we get a palindrome (65631413656).

The spelling of 21210212444 in words is "twenty-one billion, two hundred ten million, two hundred twelve thousand, four hundred forty-four".