20121271128 has 256 divisors, whose sum is σ = 67858560000. Its totient is φ = 5392852992.

The previous prime is 20121271127. The next prime is 20121271129. The reversal of 20121271128 is 82117212102.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (20121271127) and next prime (20121271129).

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20121271127) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 8969575 + ... + 8971817.

It is an arithmetic number, because the mean of its divisors is an integer number (265072500).

Almost surely, 2^20121271128 is an apocalyptic number.

20121271128 is a gapful number since it is divisible by the number (28) 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 20121271128, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33929280000).

20121271128 is an abundant number, since it is smaller than the sum of its proper divisors (47737288872).

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

20121271128 is a wasteful number, since it uses less digits than its factorization.

20121271128 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2631 (or 2621 counting only the distinct ones).

The product of its (nonzero) digits is 896, while the sum is 27.

The spelling of 20121271128 in words is "twenty billion, one hundred twenty-one million, two hundred seventy-one thousand, one hundred twenty-eight".