21300031 has 4 divisors (see below), whose sum is σ = 22552992. Its totient is φ = 20047072.

The previous prime is 21300029. The next prime is 21300061. The reversal of 21300031 is 13000312.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21300031 - 2¹ = 21300029 is a prime.

It is a super-2 number, since 2×21300031² = 907382641201922, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21299990 and 21300017.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21300061) 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, 626455 + ... + 626488.

It is an arithmetic number, because the mean of its divisors is an integer number (5638248).

Almost surely, 2^21300031 is an apocalyptic number.

21300031 is a deficient number, since it is larger than the sum of its proper divisors (1252961).

21300031 is a wasteful number, since it uses less digits than its factorization.

21300031 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1252960.

The product of its (nonzero) digits is 18, while the sum is 10.

The square root of 21300031 is about 4615.1956621578. The cubic root of 21300031 is about 277.2001186537.

Adding to 21300031 its reverse (13000312), we get a palindrome (34300343).

It can be divided in two parts, 2 and 1300031, that multiplied together give a palindrome (2600062).

The spelling of 21300031 in words is "twenty-one million, three hundred thousand, thirty-one".