21216532126431 has 8 divisors (see below), whose sum is σ = 28288803047344. Its totient is φ = 14144307978240.

The previous prime is 21216532126373. The next prime is 21216532126451. The reversal of 21216532126431 is 13462123561212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21216532126431 - 2¹⁰ = 21216532125407 is a prime.

It is a super-2 number, since 2×21216532126431² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21216532126431.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21216532126451) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10620706 + ... + 12459231.

It is an arithmetic number, because the mean of its divisors is an integer number (3536100380918).

Almost surely, 2^{21216532126431} is an apocalyptic number.

21216532126431 is a deficient number, since it is larger than the sum of its proper divisors (7072270920913).

21216532126431 is a wasteful number, since it uses less digits than its factorization.

21216532126431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23386361.

The product of its digits is 103680, while the sum is 39.

Adding to 21216532126431 its reverse (13462123561212), we get a palindrome (34678655687643).

The spelling of 21216532126431 in words is "twenty-one trillion, two hundred sixteen billion, five hundred thirty-two million, one hundred twenty-six thousand, four hundred thirty-one".