21557224543 has 2 divisors, whose sum is σ = 21557224544. Its totient is φ = 21557224542.

The previous prime is 21557224537. The next prime is 21557224547. The reversal of 21557224543 is 34542275512.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21557224543 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21557224496 and 21557224505.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21557224547) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10778612271 + 10778612272.

It is an arithmetic number, because the mean of its divisors is an integer number (10778612272).

Almost surely, 2^21557224543 is an apocalyptic number.

21557224543 is a deficient number, since it is larger than the sum of its proper divisors (1).

21557224543 is an equidigital number, since it uses as much as digits as its factorization.

21557224543 is an evil number, because the sum of its binary digits is even.

The product of its digits is 336000, while the sum is 40.

The spelling of 21557224543 in words is "twenty-one billion, five hundred fifty-seven million, two hundred twenty-four thousand, five hundred forty-three".