20101000021 has 4 divisors (see below), whose sum is σ = 20105908000. Its totient is φ = 20096092044.

The previous prime is 20100999913. The next prime is 20101000043. The reversal of 20101000021 is 12000010102.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 20101000021 - 2¹⁵ = 20100967253 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20100999968 and 20101000013.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20101000061) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2447841 + ... + 2456038.

It is an arithmetic number, because the mean of its divisors is an integer number (5026477000).

Almost surely, 2^20101000021 is an apocalyptic number.

It is an amenable number.

20101000021 is a deficient number, since it is larger than the sum of its proper divisors (4907979).

20101000021 is an equidigital number, since it uses as much as digits as its factorization.

20101000021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4907978.

The product of its (nonzero) digits is 4, while the sum is 7.

Adding to 20101000021 its reverse (12000010102), we get a palindrome (32101010123).

The spelling of 20101000021 in words is "twenty billion, one hundred one million, twenty-one", and thus it is an aban number.