21163351843 has 4 divisors (see below), whose sum is σ = 21166979688. Its totient is φ = 21159724000.

The previous prime is 21163351831. The next prime is 21163351873. The reversal of 21163351843 is 34815336112.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21163351843 is a prime.

It is a super-2 number, since 2×21163351843² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21163351873) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1805158 + ... + 1816843.

It is an arithmetic number, because the mean of its divisors is an integer number (5291744922).

Almost surely, 2^21163351843 is an apocalyptic number.

21163351843 is a deficient number, since it is larger than the sum of its proper divisors (3627845).

21163351843 is an equidigital number, since it uses as much as digits as its factorization.

21163351843 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3627844.

The product of its digits is 51840, while the sum is 37.

Adding to 21163351843 its reverse (34815336112), we get a palindrome (55978687955).

The spelling of 21163351843 in words is "twenty-one billion, one hundred sixty-three million, three hundred fifty-one thousand, eight hundred forty-three".