21005000254 has 64 divisors (see below), whose sum is σ = 37704268800. Its totient is φ = 8590256640.

The previous prime is 21005000249. The next prime is 21005000279. The reversal of 21005000254 is 45200050012.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 4827672 + ... + 4832020.

It is an arithmetic number, because the mean of its divisors is an integer number (589129200).

Almost surely, 2^21005000254 is an apocalyptic number.

21005000254 is a deficient number, since it is larger than the sum of its proper divisors (16699268546).

21005000254 is a wasteful number, since it uses less digits than its factorization.

21005000254 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4585.

The product of its (nonzero) digits is 400, while the sum is 19.

Adding to 21005000254 its reverse (45200050012), we get a palindrome (66205050266).

The spelling of 21005000254 in words is "twenty-one billion, five million, two hundred fifty-four", and thus it is an aban number.