20102001021 has 24 divisors (see below), whose sum is σ = 30448973880. Its totient is φ = 12761957376.

The previous prime is 20102001001. The next prime is 20102001037. The reversal of 20102001021 is 12010020102.

It can be written as a sum of positive squares in 4 ways, for example, as 8026188921 + 12075812100 = 89589^2 + 109890^2 .

It is not a de Polignac number, because 20102001021 - 2⁶ = 20102000957 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 = 20102000994 and 20102001012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20102001001) 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, 508476 + ... + 546581.

It is an arithmetic number, because the mean of its divisors is an integer number (1268707245).

Almost surely, 2^20102001021 is an apocalyptic number.

It is an amenable number.

20102001021 is a deficient number, since it is larger than the sum of its proper divisors (10346972859).

20102001021 is a wasteful number, since it uses less digits than its factorization.

20102001021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1055165 (or 1055162 counting only the distinct ones).

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

Adding to 20102001021 its reverse (12010020102), we get a palindrome (32112021123).

The spelling of 20102001021 in words is "twenty billion, one hundred two million, one thousand, twenty-one".