21231432011 has 4 divisors (see below), whose sum is σ = 21231934512. Its totient is φ = 21230929512.

The previous prime is 21231431983. The next prime is 21231432017. The reversal of 21231432011 is 11023413212.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21231432011 is a prime.

It is a super-3 number, since 3×21231432011³ (a number of 32 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21231432017) 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, 181400 + ... + 274533.

It is an arithmetic number, because the mean of its divisors is an integer number (5307983628).

Almost surely, 2^21231432011 is an apocalyptic number.

21231432011 is a deficient number, since it is larger than the sum of its proper divisors (502501).

21231432011 is an equidigital number, since it uses as much as digits as its factorization.

21231432011 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 502500.

The product of its (nonzero) digits is 288, while the sum is 20.

Adding to 21231432011 its reverse (11023413212), we get a palindrome (32254845223).

The spelling of 21231432011 in words is "twenty-one billion, two hundred thirty-one million, four hundred thirty-two thousand, eleven".