20001221010 has 48 divisors (see below), whose sum is σ = 52200967104. Its totient is φ = 5313372576.

The previous prime is 20001220997. The next prime is 20001221039. The reversal of 20001221010 is 1012210002.

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 = 20001220983 and 20001221001.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 398832 + ... + 446171.

It is an arithmetic number, because the mean of its divisors is an integer number (1087520148).

Almost surely, 2^20001221010 is an apocalyptic number.

20001221010 is an abundant number, since it is smaller than the sum of its proper divisors (32199746094).

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

20001221010 is a wasteful number, since it uses less digits than its factorization.

20001221010 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 845279 (or 845276 counting only the distinct ones).

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

Adding to 20001221010 its reverse (1012210002), we get a palindrome (21013431012).

The spelling of 20001221010 in words is "twenty billion, one million, two hundred twenty-one thousand, ten".