21301431 has 4 divisors (see below), whose sum is σ = 28401912. Its totient is φ = 14200952.

The previous prime is 21301421. The next prime is 21301439. The reversal of 21301431 is 13410312.

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 21301431 - 2¹⁸ = 21039287 is a prime.

It is a super-2 number, since 2×21301431² = 907501925295522, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21301431.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21301439) 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, 3550236 + ... + 3550241.

It is an arithmetic number, because the mean of its divisors is an integer number (7100478).

Almost surely, 2^21301431 is an apocalyptic number.

21301431 is a deficient number, since it is larger than the sum of its proper divisors (7100481).

21301431 is an equidigital number, since it uses as much as digits as its factorization.

21301431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7100480.

The product of its (nonzero) digits is 72, while the sum is 15.

The square root of 21301431 is about 4615.3473325417. The cubic root of 21301431 is about 277.2061917538.

Adding to 21301431 its reverse (13410312), we get a palindrome (34711743).

The spelling of 21301431 in words is "twenty-one million, three hundred one thousand, four hundred thirty-one".