21838756857481 has 16 divisors (see below), whose sum is σ = 22534309163520. Its totient is φ = 21152844195840.

The previous prime is 21838756857443. The next prime is 21838756857509. The reversal of 21838756857481 is 18475865783812.

It is not a de Polignac number, because 21838756857481 - 2²⁷ = 21838622639753 is a prime.

It is a super-2 number, since 2×21838756857481² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21838756857781) 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, 122269761 + ... + 122448241.

It is an arithmetic number, because the mean of its divisors is an integer number (1408394322720).

Almost surely, 2^{21838756857481} is an apocalyptic number.

It is an amenable number.

21838756857481 is a deficient number, since it is larger than the sum of its proper divisors (695552306039).

21838756857481 is a wasteful number, since it uses less digits than its factorization.

21838756857481 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 205464.

The product of its digits is 722534400, while the sum is 73.

The spelling of 21838756857481 in words is "twenty-one trillion, eight hundred thirty-eight billion, seven hundred fifty-six million, eight hundred fifty-seven thousand, four hundred eighty-one".