21871745585066 has 16 divisors (see below), whose sum is σ = 35728262022600. Its totient is φ = 9981228753408.

The previous prime is 21871745585059. The next prime is 21871745585089. The reversal of 21871745585066 is 66058554717812.

It can be written as a sum of positive squares in 4 ways, for example, as 4497262455625 + 17374483129441 = 2120675^2 + 4168271^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21871745584993 and 21871745585011.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4725958271 + ... + 4725962898.

Almost surely, 2^{21871745585066} is an apocalyptic number.

21871745585066 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

21871745585066 is a deficient number, since it is larger than the sum of its proper divisors (13856516437534).

21871745585066 is a wasteful number, since it uses less digits than its factorization.

21871745585066 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9451921273.

The product of its (nonzero) digits is 112896000, while the sum is 65.

The spelling of 21871745585066 in words is "twenty-one trillion, eight hundred seventy-one billion, seven hundred forty-five million, five hundred eighty-five thousand, sixty-six".