1020121020 has 144 divisors (see below), whose sum is σ = 3350178720. Its totient is φ = 257665536.

The previous prime is 1020121013. The next prime is 1020121027. The reversal of 1020121020 is 201210201.

It is an interprime number because it is at equal distance from previous prime (1020121013) and next prime (1020121027).

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a junction number, because it is equal to n+sod(n) for n = 1020120993 and 1020121011.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1020121027) 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, 192324 + ... + 197556.

It is an arithmetic number, because the mean of its divisors is an integer number (23265130).

Almost surely, 2^1020121020 is an apocalyptic number.

1020121020 is a gapful number since it is divisible by the number (10) 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 1020121020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1675089360).

1020121020 is an abundant number, since it is smaller than the sum of its proper divisors (2330057700).

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

1020121020 is a wasteful number, since it uses less digits than its factorization.

1020121020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5289 (or 5262 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

The square root of 1020121020 is about 31939.3334307402. Note that the first 3 decimals coincide. The cubic root of 1020121020 is about 1006.6625189270.

Adding to 1020121020 its reverse (201210201), we get a palindrome (1221331221).

The spelling of 1020121020 in words is "one billion, twenty million, one hundred twenty-one thousand, twenty".