21302031 has 4 divisors (see below), whose sum is σ = 28402712. Its totient is φ = 14201352.

The previous prime is 21302027. The next prime is 21302051. The reversal of 21302031 is 13020312.

It is a happy number.

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

It is not a de Polignac number, because 21302031 - 2² = 21302027 is a prime.

It is a super-2 number, since 2×21302031² = 907553049449922, 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 = 21301998 and 21302016.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21302051) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3550336 + ... + 3550341.

It is an arithmetic number, because the mean of its divisors is an integer number (7100678).

Almost surely, 2^21302031 is an apocalyptic number.

21302031 is a deficient number, since it is larger than the sum of its proper divisors (7100681).

21302031 is an equidigital number, since it uses as much as digits as its factorization.

21302031 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7100680.

The product of its (nonzero) digits is 36, while the sum is 12.

The square root of 21302031 is about 4615.4123326091. The cubic root of 21302031 is about 277.2087944296.

Adding to 21302031 its reverse (13020312), we get a palindrome (34322343).

It can be divided in two parts, 2 and 1302031, that multiplied together give a palindrome (2604062).

The spelling of 21302031 in words is "twenty-one million, three hundred two thousand, thirty-one".