21004232543 has 12 divisors (see below), whose sum is σ = 24620017752. Its totient is φ = 17866190160.

The previous prime is 21004232539. The next prime is 21004232591. The reversal of 21004232543 is 34523240012.

It is not a de Polignac number, because 21004232543 - 2² = 21004232539 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21004232243) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1629680 + ... + 1642517.

It is an arithmetic number, because the mean of its divisors is an integer number (2051668146).

Almost surely, 2^21004232543 is an apocalyptic number.

21004232543 is a deficient number, since it is larger than the sum of its proper divisors (3615785209).

21004232543 is a wasteful number, since it uses less digits than its factorization.

21004232543 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3272342 (or 3272335 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 26.

Adding to 21004232543 its reverse (34523240012), we get a palindrome (55527472555).

The spelling of 21004232543 in words is "twenty-one billion, four million, two hundred thirty-two thousand, five hundred forty-three".