21312143243 has 8 divisors (see below), whose sum is σ = 21338824080. Its totient is φ = 21285482400.

The previous prime is 21312143233. The next prime is 21312143257. The reversal of 21312143243 is 34234121312.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21312143243 - 2¹⁸ = 21311881099 is a prime.

It is a super-2 number, since 2×21312143243² (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 (21312143233) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3379193 + ... + 3385493.

It is an arithmetic number, because the mean of its divisors is an integer number (2667353010).

Almost surely, 2^21312143243 is an apocalyptic number.

21312143243 is a deficient number, since it is larger than the sum of its proper divisors (26680837).

21312143243 is a wasteful number, since it uses less digits than its factorization.

21312143243 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9997.

The product of its digits is 3456, while the sum is 26.

Adding to 21312143243 its reverse (34234121312), we get a palindrome (55546264555).

The spelling of 21312143243 in words is "twenty-one billion, three hundred twelve million, one hundred forty-three thousand, two hundred forty-three".