21155211352543 has 4 divisors (see below), whose sum is σ = 21360601754128. Its totient is φ = 20949820950960.

The previous prime is 21155211352537. The next prime is 21155211352549. The reversal of 21155211352543 is 34525311255112.

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 (21155211352537) and next prime (21155211352549).

It is a cyclic number.

It is not a de Polignac number, because 21155211352543 - 2⁵ = 21155211352511 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21155211352496 and 21155211352505.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21155211352549) 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, 102695200638 + ... + 102695200843.

It is an arithmetic number, because the mean of its divisors is an integer number (5340150438532).

Almost surely, 2^{21155211352543} is an apocalyptic number.

21155211352543 is a deficient number, since it is larger than the sum of its proper divisors (205390401585).

21155211352543 is a wasteful number, since it uses less digits than its factorization.

21155211352543 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 205390401584.

The product of its digits is 180000, while the sum is 40.

The spelling of 21155211352543 in words is "twenty-one trillion, one hundred fifty-five billion, two hundred eleven million, three hundred fifty-two thousand, five hundred forty-three".