200120001021 has 24 divisors (see below), whose sum is σ = 294540415416. Its totient is φ = 130903879680.

The previous prime is 200120001013. The next prime is 200120001023. The reversal of 200120001021 is 120100021002.

It can be written as a sum of positive squares in 4 ways, for example, as 12098900025 + 188021100996 = 109995^2 + 433614^2 .

It is not a de Polignac number, because 200120001021 - 2³ = 200120001013 is a prime.

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 = 200120000994 and 200120001012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (200120001023) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 662310 + ... + 915911.

It is an arithmetic number, because the mean of its divisors is an integer number (12272517309).

Almost surely, 2^200120001021 is an apocalyptic number.

It is an amenable number.

200120001021 is a deficient number, since it is larger than the sum of its proper divisors (94420414395).

200120001021 is a wasteful number, since it uses less digits than its factorization.

200120001021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1578493 (or 1578490 counting only the distinct ones).

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

Adding to 200120001021 its reverse (120100021002), we get a palindrome (320220022023).

The spelling of 200120001021 in words is "two hundred billion, one hundred twenty million, one thousand, twenty-one".