21220123012 has 96 divisors (see below), whose sum is σ = 43061372928. Its totient is φ = 9055200000.

The previous prime is 21220122977. The next prime is 21220123021. The reversal of 21220123012 is 21032102212.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 20189887 + ... + 20190937.

It is an arithmetic number, because the mean of its divisors is an integer number (448555968).

Almost surely, 2^21220123012 is an apocalyptic number.

21220123012 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

21220123012 is an abundant number, since it is smaller than the sum of its proper divisors (21841249916).

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

21220123012 is a wasteful number, since it uses less digits than its factorization.

21220123012 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1441 (or 1439 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 16.

Adding to 21220123012 its reverse (21032102212), we get a palindrome (42252225224).

The spelling of 21220123012 in words is "twenty-one billion, two hundred twenty million, one hundred twenty-three thousand, twelve".