21502351212 has 12 divisors (see below), whose sum is σ = 50172152856. Its totient is φ = 7167450400.

The previous prime is 21502351187. The next prime is 21502351217. The reversal of 21502351212 is 21215320512.

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

It is a super-2 number, since 2×21502351212² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21502351217) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 895931289 + ... + 895931312.

It is an arithmetic number, because the mean of its divisors is an integer number (4181012738).

Almost surely, 2^21502351212 is an apocalyptic number.

It is an amenable number.

21502351212 is an abundant number, since it is smaller than the sum of its proper divisors (28669801644).

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

21502351212 is a wasteful number, since it uses less digits than its factorization.

21502351212 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1791862608 (or 1791862606 counting only the distinct ones).

The product of its (nonzero) digits is 1200, while the sum is 24.

Adding to 21502351212 its reverse (21215320512), we get a palindrome (42717671724).

The spelling of 21502351212 in words is "twenty-one billion, five hundred two million, three hundred fifty-one thousand, two hundred twelve".