21154506356603 has 4 divisors (see below), whose sum is σ = 22398889083480. Its totient is φ = 19910123629728.

The previous prime is 21154506356549. The next prime is 21154506356653. The reversal of 21154506356603 is 30665360545112.

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 21154506356603 - 2⁶ = 21154506356539 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21154506356653) 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, 622191363413 + ... + 622191363446.

It is an arithmetic number, because the mean of its divisors is an integer number (5599722270870).

Almost surely, 2^{21154506356603} is an apocalyptic number.

21154506356603 is a deficient number, since it is larger than the sum of its proper divisors (1244382726877).

21154506356603 is a wasteful number, since it uses less digits than its factorization.

21154506356603 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1244382726876.

The product of its (nonzero) digits is 1944000, while the sum is 47.

The spelling of 21154506356603 in words is "twenty-one trillion, one hundred fifty-four billion, five hundred six million, three hundred fifty-six thousand, six hundred three".