101020021 has 4 divisors (see below), whose sum is σ = 104503500. Its totient is φ = 97536544.

The previous prime is 101020009. The next prime is 101020037. The reversal of 101020021 is 120020101.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 120020101 = 59 ⋅2034239.

It can be written as a sum of positive squares in 2 ways, for example, as 27300625 + 73719396 = 5225^2 + 8586^2 .

It is a cyclic number.

It is not a de Polignac number, because 101020021 - 2¹³ = 101011829 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 101019986 and 101020013.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (101020421) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1741696 + ... + 1741753.

It is an arithmetic number, because the mean of its divisors is an integer number (26125875).

Almost surely, 2^101020021 is an apocalyptic number.

It is an amenable number.

101020021 is a deficient number, since it is larger than the sum of its proper divisors (3483479).

101020021 is an equidigital number, since it uses as much as digits as its factorization.

101020021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3483478.

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

The square root of 101020021 is about 10050.8716537423. The cubic root of 101020021 is about 465.7317203603.

Adding to 101020021 its reverse (120020101), we get a palindrome (221040122).

The spelling of 101020021 in words is "one hundred one million, twenty thousand, twenty-one".