21121222012 has 48 divisors (see below), whose sum is σ = 40493934432. Its totient is φ = 9559802880.

The previous prime is 21121222009. The next prime is 21121222049. The reversal of 21121222012 is 21022212112.

It is a happy number.

It is a super-2 number, since 2×21121222012² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 14738448 + ... + 14739880.

It is an arithmetic number, because the mean of its divisors is an integer number (843623634).

Almost surely, 2^21121222012 is an apocalyptic number.

21121222012 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

21121222012 is a deficient number, since it is larger than the sum of its proper divisors (19372712420).

21121222012 is a wasteful number, since it uses less digits than its factorization.

21121222012 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2638 (or 2636 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 16.

Adding to 21121222012 its reverse (21022212112), we get a palindrome (42143434124).

The spelling of 21121222012 in words is "twenty-one billion, one hundred twenty-one million, two hundred twenty-two thousand, twelve".