21875382081 has 144 divisors (see below), whose sum is σ = 39752693760. Its totient is φ = 11522165760.

The previous prime is 21875382071. The next prime is 21875382103. The reversal of 21875382081 is 18028357812.

21875382081 is a `hidden beast` number, since 2 + 18 + 7 + 538 + 20 + 81 = 666.

It is not a de Polignac number, because 21875382081 - 2⁵ = 21875382049 is a prime.

It is a super-2 number, since 2×21875382081² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21875382071) by changing a digit.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 64911945 + ... + 64912281.

Almost surely, 2^21875382081 is an apocalyptic number.

21875382081 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21875382081 is a deficient number, since it is larger than the sum of its proper divisors (17877311679).

21875382081 is a wasteful number, since it uses less digits than its factorization.

21875382081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 564 (or 554 counting only the distinct ones).

The product of its (nonzero) digits is 215040, while the sum is 45.

The spelling of 21875382081 in words is "twenty-one billion, eight hundred seventy-five million, three hundred eighty-two thousand, eighty-one".