21553645603 has 16 divisors (see below), whose sum is σ = 24955776000. Its totient is φ = 18232486272.

The previous prime is 21553645579. The next prime is 21553645613. The reversal of 21553645603 is 30654635512.

It is not a de Polignac number, because 21553645603 - 2²¹ = 21551548451 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21553645613) 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, 1435308 + ... + 1450246.

It is an arithmetic number, because the mean of its divisors is an integer number (1559736000).

Almost surely, 2^21553645603 is an apocalyptic number.

21553645603 is a deficient number, since it is larger than the sum of its proper divisors (3402130397).

21553645603 is a wasteful number, since it uses less digits than its factorization.

21553645603 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17634.

The product of its (nonzero) digits is 324000, while the sum is 40.

The spelling of 21553645603 in words is "twenty-one billion, five hundred fifty-three million, six hundred forty-five thousand, six hundred three".