20111010021 has 16 divisors (see below), whose sum is σ = 29810173120. Its totient is φ = 13400102160.

The previous prime is 20111009981. The next prime is 20111010061. The reversal of 20111010021 is 12001011102.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (20111009981) and next prime (20111010061).

It is not a de Polignac number, because 20111010021 - 2²¹ = 20108912869 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20111009985 and 20111010012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20111010061) 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 15 ways as a sum of consecutive naturals, for example, 149875 + ... + 250368.

It is an arithmetic number, because the mean of its divisors is an integer number (1863135820).

Almost surely, 2^20111010021 is an apocalyptic number.

It is an amenable number.

20111010021 is a deficient number, since it is larger than the sum of its proper divisors (9699163099).

20111010021 is a wasteful number, since it uses less digits than its factorization.

20111010021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 402113 (or 402107 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 9.

Adding to 20111010021 its reverse (12001011102), we get a palindrome (32112021123).

The spelling of 20111010021 in words is "twenty billion, one hundred eleven million, ten thousand, twenty-one".