21555430503 has 16 divisors (see below), whose sum is σ = 29738171520. Its totient is φ = 13871706464.

The previous prime is 21555430499. The next prime is 21555430537. The reversal of 21555430503 is 30503455512.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 21555430503 - 2² = 21555430499 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21555430543) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 410500 + ... + 460022.

It is an arithmetic number, because the mean of its divisors is an integer number (1858635720).

Almost surely, 2^21555430503 is an apocalyptic number.

21555430503 is a deficient number, since it is larger than the sum of its proper divisors (8182741017).

21555430503 is a wasteful number, since it uses less digits than its factorization.

21555430503 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 54558.

The product of its (nonzero) digits is 45000, while the sum is 33.

The spelling of 21555430503 in words is "twenty-one billion, five hundred fifty-five million, four hundred thirty thousand, five hundred three".