21854841381 has 6 divisors (see below), whose sum is σ = 31568104230. Its totient is φ = 14569894248.

The previous prime is 21854841361. The next prime is 21854841391. The reversal of 21854841381 is 18314845812.

21854841381 is a `hidden beast` number, since 2 + 1 + 85 + 484 + 13 + 81 = 666.

It can be written as a sum of positive squares in only one way, i.e., 21738848481 + 115992900 = 147441^2 + 10770^2 .

It is not a de Polignac number, because 21854841381 - 2¹¹ = 21854839333 is a prime.

It is a super-2 number, since 2×21854841381² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21854841361) 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, 1214157846 + ... + 1214157863.

It is an arithmetic number, because the mean of its divisors is an integer number (5261350705).

Almost surely, 2^21854841381 is an apocalyptic number.

It is an amenable number.

21854841381 is a deficient number, since it is larger than the sum of its proper divisors (9713262849).

21854841381 is a wasteful number, since it uses less digits than its factorization.

21854841381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2428315715 (or 2428315712 counting only the distinct ones).

The product of its digits is 245760, while the sum is 45.

The spelling of 21854841381 in words is "twenty-one billion, eight hundred fifty-four million, eight hundred forty-one thousand, three hundred eighty-one".