21256016124603 has 32 divisors (see below), whose sum is σ = 31023034018816. Its totient is φ = 12866244830208.

The previous prime is 21256016124559. The next prime is 21256016124661. The reversal of 21256016124603 is 30642161065212.

It is not a de Polignac number, because 21256016124603 - 2²⁶ = 21255949015739 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21256016124403) 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 31 ways as a sum of consecutive naturals, for example, 4285075 + ... + 7802172.

It is an arithmetic number, because the mean of its divisors is an integer number (969469813088).

Almost surely, 2^{21256016124603} is an apocalyptic number.

21256016124603 is a deficient number, since it is larger than the sum of its proper divisors (9767017894213).

21256016124603 is a wasteful number, since it uses less digits than its factorization.

21256016124603 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12088003.

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

Adding to 21256016124603 its reverse (30642161065212), we get a palindrome (51898177189815).

The spelling of 21256016124603 in words is "twenty-one trillion, two hundred fifty-six billion, sixteen million, one hundred twenty-four thousand, six hundred three".