21081685041 has 6 divisors (see below), whose sum is σ = 30451322850. Its totient is φ = 14054456688.

The previous prime is 21081685019. The next prime is 21081685063. The reversal of 21081685041 is 14058618012.

21081685041 is a `hidden beast` number, since 2 + 10 + 81 + 68 + 504 + 1 = 666.

It is an interprime number because it is at equal distance from previous prime (21081685019) and next prime (21081685063).

It can be written as a sum of positive squares in only one way, i.e., 15770336400 + 5311348641 = 125580^2 + 72879^2 .

It is not a de Polignac number, because 21081685041 - 2¹⁸ = 21081422897 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21081684987 and 21081685005.

It is not an unprimeable number, because it can be changed into a prime (21081685741) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1171204716 + ... + 1171204733.

It is an arithmetic number, because the mean of its divisors is an integer number (5075220475).

Almost surely, 2^21081685041 is an apocalyptic number.

It is an amenable number.

21081685041 is a deficient number, since it is larger than the sum of its proper divisors (9369637809).

21081685041 is a wasteful number, since it uses less digits than its factorization.

21081685041 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2342409455 (or 2342409452 counting only the distinct ones).

The product of its (nonzero) digits is 15360, while the sum is 36.

The spelling of 21081685041 in words is "twenty-one billion, eighty-one million, six hundred eighty-five thousand, forty-one".