20101001001021 has 6 divisors (see below), whose sum is σ = 29034779223710. Its totient is φ = 13400667334008.

The previous prime is 20101001001019. The next prime is 20101001001079. The reversal of 20101001001021 is 12010010010102.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 11810315784996 + 8290685216025 = 3436614^2 + 2879355^2 .

It is not a de Polignac number, because 20101001001021 - 2¹ = 20101001001019 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: 2233444555669 = 20101001001021 / (2 + 0 + 1 + 0 + 1 + 0 + 0 + 1 + 0 + 0 + 1 + 0 + 2 + 1).

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20101001000994 and 20101001001012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20101001000021) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1116722277826 + ... + 1116722277843.

Almost surely, 2^{20101001001021} is an apocalyptic number.

It is an amenable number.

20101001001021 is a deficient number, since it is larger than the sum of its proper divisors (8933778222689).

20101001001021 is a wasteful number, since it uses less digits than its factorization.

20101001001021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2233444555675 (or 2233444555672 counting only the distinct ones).

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

Adding to 20101001001021 its reverse (12010010010102), we get a palindrome (32111011011123).

The spelling of 20101001001021 in words is "twenty trillion, one hundred one billion, one million, one thousand, twenty-one".