21320431015 has 16 divisors (see below), whose sum is σ = 27574934688. Its totient is φ = 15731531136.

The previous prime is 21320431007. The next prime is 21320431019. The reversal of 21320431015 is 51013402312.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 21320431015 - 2³ = 21320431007 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21320431019) 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, 52177 + ... + 212986.

It is an arithmetic number, because the mean of its divisors is an integer number (1723433418).

Almost surely, 2^21320431015 is an apocalyptic number.

21320431015 is a deficient number, since it is larger than the sum of its proper divisors (6254503673).

21320431015 is a wasteful number, since it uses less digits than its factorization.

21320431015 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 266418.

The product of its (nonzero) digits is 720, while the sum is 22.

Adding to 21320431015 its reverse (51013402312), we get a palindrome (72333833327).

The spelling of 21320431015 in words is "twenty-one billion, three hundred twenty million, four hundred thirty-one thousand, fifteen".