21211011431 has 4 divisors (see below), whose sum is σ = 21211794864. Its totient is φ = 21210228000.

The previous prime is 21211011427. The next prime is 21211011533. The reversal of 21211011431 is 13411011212.

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 21211011431 - 2² = 21211011427 is a prime.

It is a super-2 number, since 2×21211011431² (a number of 21 digits) contains 22 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 (21211011421) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 349595 + ... + 405756.

It is an arithmetic number, because the mean of its divisors is an integer number (5302948716).

Almost surely, 2^21211011431 is an apocalyptic number.

21211011431 is a deficient number, since it is larger than the sum of its proper divisors (783433).

21211011431 is an equidigital number, since it uses as much as digits as its factorization.

21211011431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 783432.

The product of its (nonzero) digits is 48, while the sum is 17.

Adding to 21211011431 its reverse (13411011212), we get a palindrome (34622022643).

The spelling of 21211011431 in words is "twenty-one billion, two hundred eleven million, eleven thousand, four hundred thirty-one".