18941981571 has 16 divisors (see below), whose sum is σ = 28064793600. Its totient is φ = 12626818344.

The previous prime is 18941981561. The next prime is 18941981599. The reversal of 18941981571 is 17518914981.

18941981571 is a `hidden beast` number, since 1 + 89 + 419 + 81 + 5 + 71 = 666.

It is not a de Polignac number, because 18941981571 - 2¹⁴ = 18941965187 is a prime.

It is a super-2 number, since 2×18941981571² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (18941981561) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 343690 + ... + 394976.

It is an arithmetic number, because the mean of its divisors is an integer number (1754049600).

Almost surely, 2^18941981571 is an apocalyptic number.

18941981571 is a deficient number, since it is larger than the sum of its proper divisors (9122812029).

18941981571 is a wasteful number, since it uses less digits than its factorization.

18941981571 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 64975 (or 64969 counting only the distinct ones).

The product of its digits is 725760, while the sum is 54.

The spelling of 18941981571 in words is "eighteen billion, nine hundred forty-one million, nine hundred eighty-one thousand, five hundred seventy-one".