21004533555 has 32 divisors (see below), whose sum is σ = 34012457280. Its totient is φ = 11067555840.

The previous prime is 21004533553. The next prime is 21004533619. The reversal of 21004533555 is 55533540012.

It is a happy number.

It is not a de Polignac number, because 21004533555 - 2¹ = 21004533553 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21004533553) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1837939 + ... + 1849331.

It is an arithmetic number, because the mean of its divisors is an integer number (1062889290).

Almost surely, 2^21004533555 is an apocalyptic number.

21004533555 is a deficient number, since it is larger than the sum of its proper divisors (13007923725).

21004533555 is a wasteful number, since it uses less digits than its factorization.

21004533555 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12871.

The product of its (nonzero) digits is 45000, while the sum is 33.

The spelling of 21004533555 in words is "twenty-one billion, four million, five hundred thirty-three thousand, five hundred fifty-five".