21553043541 has 4 divisors (see below), whose sum is σ = 28737391392. Its totient is φ = 14368695692.

The previous prime is 21553043537. The next prime is 21553043569. The reversal of 21553043541 is 14534035512.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21553043541 - 2² = 21553043537 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21553043521) 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, 3592173921 + ... + 3592173926.

It is an arithmetic number, because the mean of its divisors is an integer number (7184347848).

Almost surely, 2^21553043541 is an apocalyptic number.

It is an amenable number.

21553043541 is a deficient number, since it is larger than the sum of its proper divisors (7184347851).

21553043541 is an equidigital number, since it uses as much as digits as its factorization.

21553043541 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7184347850.

The product of its (nonzero) digits is 36000, while the sum is 33.

The spelling of 21553043541 in words is "twenty-one billion, five hundred fifty-three million, forty-three thousand, five hundred forty-one".