20210010021 has 6 divisors (see below), whose sum is σ = 29192236710. Its totient is φ = 13473340008.

The previous prime is 20210009983. The next prime is 20210010053. The reversal of 20210010021 is 12001001202.

It can be written as a sum of positive squares in only one way, i.e., 20209749921 + 260100 = 142161^2 + 510^2 .

It is not a de Polignac number, because 20210010021 - 2⁶ = 20210009957 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9), and also a Moran number because the ratio is a prime number: 2245556669 = 20210010021 / (2 + 0 + 2 + 1 + 0 + 0 + 1 + 0 + 0 + 2 + 1).

It is a junction number, because it is equal to n+sod(n) for n = 20210009985 and 20210010012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20210010221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1122778326 + ... + 1122778343.

It is an arithmetic number, because the mean of its divisors is an integer number (4865372785).

Almost surely, 2^20210010021 is an apocalyptic number.

It is an amenable number.

20210010021 is a deficient number, since it is larger than the sum of its proper divisors (8982226689).

20210010021 is a wasteful number, since it uses less digits than its factorization.

20210010021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2245556675 (or 2245556672 counting only the distinct ones).

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

Adding to 20210010021 its reverse (12001001202), we get a palindrome (32211011223).

The spelling of 20210010021 in words is "twenty billion, two hundred ten million, ten thousand, twenty-one".