2123561020 has 192 divisors, whose sum is σ = 5570611200. Its totient is φ = 678053376.

The previous prime is 2123561009. The next prime is 2123561029. The reversal of 2123561020 is 201653212.

It is a super-2 number, since 2×2123561020² = 9019022811326880800, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 2123560982 and 2123561000.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2123561029) 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, 6784384 + ... + 6784696.

It is an arithmetic number, because the mean of its divisors is an integer number (29013600).

Almost surely, 2^2123561020 is an apocalyptic number.

2123561020 is a gapful number since it is divisible by the number (20) 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 2123561020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2785305600).

2123561020 is an abundant number, since it is smaller than the sum of its proper divisors (3447050180).

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

2123561020 is a wasteful number, since it uses less digits than its factorization.

2123561020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 409 (or 393 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 22.

The square root of 2123561020 is about 46082.1117137659. Note that the first 3 decimals coincide. The cubic root of 2123561020 is about 1285.3505319350.

The spelling of 2123561020 in words is "two billion, one hundred twenty-three million, five hundred sixty-one thousand, twenty".