21381232311 has 20 divisors (see below), whose sum is σ = 32718891744. Its totient is φ = 13906490400.

The previous prime is 21381232309. The next prime is 21381232337. The reversal of 21381232311 is 11323218312.

21381232311 is a `hidden beast` number, since 21 + 381 + 232 + 31 + 1 = 666.

It is not a de Polignac number, because 21381232311 - 2¹ = 21381232309 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21381232111) 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 19 ways as a sum of consecutive naturals, for example, 3215775 + ... + 3222416.

Almost surely, 2^21381232311 is an apocalyptic number.

21381232311 is a deficient number, since it is larger than the sum of its proper divisors (11337659433).

21381232311 is an equidigital number, since it uses as much as digits as its factorization.

21381232311 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6438244 (or 6438235 counting only the distinct ones).

The product of its digits is 1728, while the sum is 27.

The spelling of 21381232311 in words is "twenty-one billion, three hundred eighty-one million, two hundred thirty-two thousand, three hundred eleven".