21012020101 has 4 divisors (see below), whose sum is σ = 21151172704. Its totient is φ = 20872867500.

The previous prime is 21012020059. The next prime is 21012020119. The reversal of 21012020101 is 10102021012.

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 21012020101 - 2²¹ = 21009922949 is a prime.

It is a super-3 number, since 3×21012020101³ (a number of 32 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21012021101) 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, 69576075 + ... + 69576376.

It is an arithmetic number, because the mean of its divisors is an integer number (5287793176).

Almost surely, 2^21012020101 is an apocalyptic number.

It is an amenable number.

21012020101 is a deficient number, since it is larger than the sum of its proper divisors (139152603).

21012020101 is a wasteful number, since it uses less digits than its factorization.

21012020101 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 139152602.

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

Adding to 21012020101 its reverse (10102021012), we get a palindrome (31114041113).

It can be divided in two parts, 2101 and 2020101, that added together give a palindrome (2022202).

The spelling of 21012020101 in words is "twenty-one billion, twelve million, twenty thousand, one hundred one".