21551403203 has 4 divisors (see below), whose sum is σ = 23510621688. Its totient is φ = 19592184720.

The previous prime is 21551403193. The next prime is 21551403229. The reversal of 21551403203 is 30230415512.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21551403203 - 2¹⁴ = 21551386819 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21551403233) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 979609226 + ... + 979609247.

It is an arithmetic number, because the mean of its divisors is an integer number (5877655422).

Almost surely, 2^21551403203 is an apocalyptic number.

21551403203 is a deficient number, since it is larger than the sum of its proper divisors (1959218485).

21551403203 is a wasteful number, since it uses less digits than its factorization.

21551403203 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1959218484.

The product of its (nonzero) digits is 3600, while the sum is 26.

Adding to 21551403203 its reverse (30230415512), we get a palindrome (51781818715).

The spelling of 21551403203 in words is "twenty-one billion, five hundred fifty-one million, four hundred three thousand, two hundred three".