21154555503 has 12 divisors (see below), whose sum is σ = 30562660128. Its totient is φ = 14100230880.

The previous prime is 21154555493. The next prime is 21154555547. The reversal of 21154555503 is 30555545112.

21154555503 is a `hidden beast` number, since 2 + 1 + 1 + 54 + 55 + 550 + 3 = 666.

It is not a de Polignac number, because 21154555503 - 2⁶ = 21154555439 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21154550503) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 185575 + ... + 277032.

It is an arithmetic number, because the mean of its divisors is an integer number (2546888344).

Almost surely, 2^21154555503 is an apocalyptic number.

21154555503 is a deficient number, since it is larger than the sum of its proper divisors (9408104625).

21154555503 is a wasteful number, since it uses less digits than its factorization.

21154555503 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 467694 (or 467691 counting only the distinct ones).

The product of its (nonzero) digits is 75000, while the sum is 36.

The spelling of 21154555503 in words is "twenty-one billion, one hundred fifty-four million, five hundred fifty-five thousand, five hundred three".