21021012012 has 288 divisors, whose sum is σ = 69249954816. Its totient is φ = 4820175360.

The previous prime is 21021011993. The next prime is 21021012029.

21021012012 is nontrivially palindromic in base 10.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 3035578 + ... + 3042494.

It is an arithmetic number, because the mean of its divisors is an integer number (240451232).

Almost surely, 2^21021012012 is an apocalyptic number.

21021012012 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21021012012, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34624977408).

21021012012 is an abundant number, since it is smaller than the sum of its proper divisors (48228942804).

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

21021012012 is a wasteful number, since it uses less digits than its factorization.

21021012012 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6989 (or 6976 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 12.

It can be divided in two parts, 210210 and 12012, that added together give a palindrome (222222).

The spelling of 21021012012 in words is "twenty-one billion, twenty-one million, twelve thousand, twelve".