21745305543 has 12 divisors (see below), whose sum is σ = 31395589800. Its totient is φ = 13381726176.

The previous prime is 21745305521. The next prime is 21745305599. The reversal of 21745305543 is 34550354712.

It is not a de Polignac number, because 21745305543 - 2⁵ = 21745305511 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21745305503) 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, 21444568 + ... + 21445581.

It is an arithmetic number, because the mean of its divisors is an integer number (2616299150).

Almost surely, 2^21745305543 is an apocalyptic number.

21745305543 is a deficient number, since it is larger than the sum of its proper divisors (9650284257).

21745305543 is a wasteful number, since it uses less digits than its factorization.

21745305543 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42890178 (or 42890165 counting only the distinct ones).

The product of its (nonzero) digits is 252000, while the sum is 39.

The spelling of 21745305543 in words is "twenty-one billion, seven hundred forty-five million, three hundred five thousand, five hundred forty-three".