21232056387 has 6 divisors (see below), whose sum is σ = 28309745028. Its totient is φ = 14154536004.

The previous prime is 21232056343. The next prime is 21232056389. The reversal of 21232056387 is 78365023212.

It is not a de Polignac number, because 21232056387 - 2⁶ = 21232056323 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21232056389) 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 5 ways as a sum of consecutive naturals, for example, 210318 + ... + 294444.

It is an arithmetic number, because the mean of its divisors is an integer number (4718290838).

Almost surely, 2^21232056387 is an apocalyptic number.

21232056387 is a deficient number, since it is larger than the sum of its proper divisors (7077688641).

21232056387 is an frugal number, since it uses more digits than its factorization.

21232056387 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 168257 (or 84130 counting only the distinct ones).

The product of its (nonzero) digits is 120960, while the sum is 39.

Adding to 21232056387 its reverse (78365023212), we get a palindrome (99597079599).

The spelling of 21232056387 in words is "twenty-one billion, two hundred thirty-two million, fifty-six thousand, three hundred eighty-seven".