21237452543 has 4 divisors (see below), whose sum is σ = 21243049560. Its totient is φ = 21231855528.

The previous prime is 21237452519. The next prime is 21237452567. The reversal of 21237452543 is 34525473212.

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

It is an interprime number because it is at equal distance from previous prime (21237452519) and next prime (21237452567).

It is a cyclic number.

It is not a de Polignac number, because 21237452543 - 2¹⁸ = 21237190399 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21237452497 and 21237452506.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21237422543) 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, 2792813 + ... + 2800406.

It is an arithmetic number, because the mean of its divisors is an integer number (5310762390).

Almost surely, 2^21237452543 is an apocalyptic number.

21237452543 is a deficient number, since it is larger than the sum of its proper divisors (5597017).

21237452543 is an equidigital number, since it uses as much as digits as its factorization.

21237452543 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5597016.

The product of its digits is 201600, while the sum is 38.

The spelling of 21237452543 in words is "twenty-one billion, two hundred thirty-seven million, four hundred fifty-two thousand, five hundred forty-three".