21981523456893 has 32 divisors (see below), whose sum is σ = 39351538501632. Its totient is φ = 10540590667200.

The previous prime is 21981523456889. The next prime is 21981523456897. The reversal of 21981523456893 is 39865432518912.

It is an interprime number because it is at equal distance from previous prime (21981523456889) and next prime (21981523456897).

It is not a de Polignac number, because 21981523456893 - 2² = 21981523456889 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21981523456897) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (31) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3659924313 + ... + 3659930318.

It is an arithmetic number, because the mean of its divisors is an integer number (1229735578176).

Almost surely, 2^{21981523456893} is an apocalyptic number.

It is an amenable number.

21981523456893 is a deficient number, since it is larger than the sum of its proper divisors (17370015044739).

21981523456893 is a wasteful number, since it uses less digits than its factorization.

21981523456893 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7319854665.

The product of its digits is 111974400, while the sum is 66.

The spelling of 21981523456893 in words is "twenty-one trillion, nine hundred eighty-one billion, five hundred twenty-three million, four hundred fifty-six thousand, eight hundred ninety-three".