21000013122312 has 192 divisors, whose sum is σ = 67357984636800. Its totient is φ = 5783064698880.

The previous prime is 21000013122311. The next prime is 21000013122313. The reversal of 21000013122312 is 21322131000012.

It is an interprime number because it is at equal distance from previous prime (21000013122311) and next prime (21000013122313).

It is a super-2 number, since 2×21000013122312² (a number of 27 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is not an unprimeable number, because it can be changed into a prime (21000013122311) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 7188387 + ... + 9678477.

It is an arithmetic number, because the mean of its divisors is an integer number (350822836650).

Almost surely, 2^{21000013122312} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21000013122312, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33678992318400).

21000013122312 is an abundant number, since it is smaller than the sum of its proper divisors (46357971514488).

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

21000013122312 is a wasteful number, since it uses less digits than its factorization.

21000013122312 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2490716 (or 2490709 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 18.

Adding to 21000013122312 its reverse (21322131000012), we get a palindrome (42322144122324).

The spelling of 21000013122312 in words is "twenty-one trillion, thirteen million, one hundred twenty-two thousand, three hundred twelve".