21155020543 has 8 divisors (see below), whose sum is σ = 22297420800. Its totient is φ = 20040148128.

The previous prime is 21155020517. The next prime is 21155020553. The reversal of 21155020543 is 34502055112.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21155020543 - 2⁵ = 21155020511 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 (21155020553) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6880383 + ... + 6883456.

It is an arithmetic number, because the mean of its divisors is an integer number (2787177600).

Almost surely, 2^21155020543 is an apocalyptic number.

21155020543 is a deficient number, since it is larger than the sum of its proper divisors (1142400257).

21155020543 is a wasteful number, since it uses less digits than its factorization.

21155020543 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13763921.

The product of its (nonzero) digits is 6000, while the sum is 28.

Adding to 21155020543 its reverse (34502055112), we get a palindrome (55657075655).

The spelling of 21155020543 in words is "twenty-one billion, one hundred fifty-five million, twenty thousand, five hundred forty-three".