21781522880091 has 32 divisors (see below), whose sum is σ = 36262067089920. Its totient is φ = 12821230854432.

The previous prime is 21781522880057. The next prime is 21781522880147. The reversal of 21781522880091 is 19008822518712.

It is a happy number.

21781522880091 is a `hidden beast` number, since 21 + 7 + 8 + 1 + 522 + 8 + 8 + 0 + 0 + 91 = 666.

It is not a de Polignac number, because 21781522880091 - 2²⁶ = 21781455771227 is a prime.

It is a super-3 number, since 3×21781522880091³ (a number of 41 digits) contains 333 as substring.

It is not an unprimeable number, because it can be changed into a prime (21781522880011) 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 31 ways as a sum of consecutive naturals, for example, 1349027161 + ... + 1349043306.

It is an arithmetic number, because the mean of its divisors is an integer number (1133189596560).

Almost surely, 2^{21781522880091} is an apocalyptic number.

21781522880091 is a deficient number, since it is larger than the sum of its proper divisors (14480544209829).

21781522880091 is a wasteful number, since it uses less digits than its factorization.

21781522880091 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2698070512 (or 2698070506 counting only the distinct ones).

The product of its (nonzero) digits is 1290240, while the sum is 54.

The spelling of 21781522880091 in words is "twenty-one trillion, seven hundred eighty-one billion, five hundred twenty-two million, eight hundred eighty thousand, ninety-one".