21161843788 has 48 divisors (see below), whose sum is σ = 40104096480. Its totient is φ = 9736505856.

The previous prime is 21161843767. The next prime is 21161843803. The reversal of 21161843788 is 88734816112.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1728906 + ... + 1741102.

It is an arithmetic number, because the mean of its divisors is an integer number (835502010).

Almost surely, 2^21161843788 is an apocalyptic number.

It is an amenable number.

21161843788 is a deficient number, since it is larger than the sum of its proper divisors (18942252692).

21161843788 is a wasteful number, since it uses less digits than its factorization.

21161843788 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12874 (or 12872 counting only the distinct ones).

The product of its digits is 516096, while the sum is 49.

The spelling of 21161843788 in words is "twenty-one billion, one hundred sixty-one million, eight hundred forty-three thousand, seven hundred eighty-eight".