20021021210 has 24 divisors (see below), whose sum is σ = 38282414940. Its totient is φ = 7537324544.

The previous prime is 20021021203. The next prime is 20021021249. The reversal of 20021021210 is 1212012002.

It is a happy number.

It can be written as a sum of positive squares in 6 ways, for example, as 18232830841 + 1788190369 = 135029^2 + 42287^2 .

It is a junction number, because it is equal to n+sod(n) for n = 20021021191 and 20021021200.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3460955 + ... + 3466734.

Almost surely, 2^20021021210 is an apocalyptic number.

20021021210 is a deficient number, since it is larger than the sum of its proper divisors (18261393730).

20021021210 is a wasteful number, since it uses less digits than its factorization.

20021021210 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6927730 (or 6927713 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 11.

Adding to 20021021210 its reverse (1212012002), we get a palindrome (21233033212).

The spelling of 20021021210 in words is "twenty billion, twenty-one million, twenty-one thousand, two hundred ten".