21555731603 has 8 divisors (see below), whose sum is σ = 24649351008. Its totient is φ = 18465669504.

The previous prime is 21555731573. The next prime is 21555731609. The reversal of 21555731603 is 30613755512.

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 21555731603 - 2⁸ = 21555731347 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21555731609) 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, 876326 + ... + 900587.

It is an arithmetic number, because the mean of its divisors is an integer number (3081168876).

Almost surely, 2^21555731603 is an apocalyptic number.

21555731603 is a deficient number, since it is larger than the sum of its proper divisors (3093619405).

21555731603 is a wasteful number, since it uses less digits than its factorization.

21555731603 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1778653.

The product of its (nonzero) digits is 94500, while the sum is 38.

The spelling of 21555731603 in words is "twenty-one billion, five hundred fifty-five million, seven hundred thirty-one thousand, six hundred three".