10102021021 has 4 divisors (see below), whose sum is σ = 10102256892. Its totient is φ = 10101785152.

The previous prime is 10102021009. The next prime is 10102021043. The reversal of 10102021021 is 12012020101.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12012020101 = 23741 ⋅505961.

It can be written as a sum of positive squares in 2 ways, for example, as 3953265625 + 6148755396 = 62875^2 + 78414^2 .

It is a cyclic number.

It is not a de Polignac number, because 10102021021 - 2¹⁹ = 10101496733 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 10102020989 and 10102021007.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (10102021001) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 33580 + ... + 146053.

It is an arithmetic number, because the mean of its divisors is an integer number (2525564223).

Almost surely, 2^10102021021 is an apocalyptic number.

It is an amenable number.

10102021021 is a deficient number, since it is larger than the sum of its proper divisors (235871).

10102021021 is an equidigital number, since it uses as much as digits as its factorization.

10102021021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 235870.

The product of its (nonzero) digits is 8, while the sum is 10.

Adding to 10102021021 its reverse (12012020101), we get a palindrome (22114041122).

The spelling of 10102021021 in words is "ten billion, one hundred two million, twenty-one thousand, twenty-one".