21121534543 has 2 divisors, whose sum is σ = 21121534544. Its totient is φ = 21121534542.

The previous prime is 21121534537. The next prime is 21121534559. The reversal of 21121534543 is 34543512112.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21121534543 is a prime.

It is a super-2 number, since 2×21121534543² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21121534523) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10560767271 + 10560767272.

It is an arithmetic number, because the mean of its divisors is an integer number (10560767272).

Almost surely, 2^21121534543 is an apocalyptic number.

21121534543 is a deficient number, since it is larger than the sum of its proper divisors (1).

21121534543 is an equidigital number, since it uses as much as digits as its factorization.

21121534543 is an evil number, because the sum of its binary digits is even.

The product of its digits is 14400, while the sum is 31.

The spelling of 21121534543 in words is "twenty-one billion, one hundred twenty-one million, five hundred thirty-four thousand, five hundred forty-three".