21121222161408 has 352 divisors, whose sum is σ = 61310774802816. Its totient is φ = 6438499909632.

The previous prime is 21121222161401. The next prime is 21121222161469. The reversal of 21121222161408 is 80416122212112.

It is a super-2 number, since 2×21121222161408² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21121222161401) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 433382610 + ... + 433431342.

It is an arithmetic number, because the mean of its divisors is an integer number (174178337508).

Almost surely, 2^{21121222161408} 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 21121222161408, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30655387401408).

21121222161408 is an abundant number, since it is smaller than the sum of its proper divisors (40189552641408).

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

21121222161408 is a wasteful number, since it uses less digits than its factorization.

21121222161408 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 49009 (or 48991 counting only the distinct ones).

The product of its (nonzero) digits is 6144, while the sum is 33.

The spelling of 21121222161408 in words is "twenty-one trillion, one hundred twenty-one billion, two hundred twenty-two million, one hundred sixty-one thousand, four hundred eight".