21211212084 has 24 divisors (see below), whose sum is σ = 49946893920. Its totient is φ = 7005537504.

The previous prime is 21211212083. The next prime is 21211212107. The reversal of 21211212084 is 48021211212.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21211212083) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8106954 + ... + 8109569.

It is an arithmetic number, because the mean of its divisors is an integer number (2081120580).

Almost surely, 2^21211212084 is an apocalyptic number.

It is an amenable number.

21211212084 is an abundant number, since it is smaller than the sum of its proper divisors (28735681836).

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

21211212084 is a wasteful number, since it uses less digits than its factorization.

21211212084 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16216639 (or 16216637 counting only the distinct ones).

The product of its (nonzero) digits is 512, while the sum is 24.

Adding to 21211212084 its reverse (48021211212), we get a palindrome (69232423296).

The spelling of 21211212084 in words is "twenty-one billion, two hundred eleven million, two hundred twelve thousand, eighty-four".