21431253242 has 32 divisors (see below), whose sum is σ = 37157957760. Its totient is φ = 9080709120.

The previous prime is 21431253241. The next prime is 21431253271. The reversal of 21431253242 is 24235213412.

It is not an unprimeable number, because it can be changed into a prime (21431253241) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 446138 + ... + 491834.

It is an arithmetic number, because the mean of its divisors is an integer number (1161186180).

Almost surely, 2^21431253242 is an apocalyptic number.

21431253242 is a deficient number, since it is larger than the sum of its proper divisors (15726704518).

21431253242 is a wasteful number, since it uses less digits than its factorization.

21431253242 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 46086.

The product of its digits is 11520, while the sum is 29.

Adding to 21431253242 its reverse (24235213412), we get a palindrome (45666466654).

The spelling of 21431253242 in words is "twenty-one billion, four hundred thirty-one million, two hundred fifty-three thousand, two hundred forty-two".