21000253405 has 8 divisors (see below), whose sum is σ = 26526636000. Its totient is φ = 15915981456.

The previous prime is 21000253403. The next prime is 21000253411. The reversal of 21000253405 is 50435200012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21000253405 - 2¹ = 21000253403 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21000253403) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 110527555 + ... + 110527744.

It is an arithmetic number, because the mean of its divisors is an integer number (3315829500).

Almost surely, 2^21000253405 is an apocalyptic number.

It is an amenable number.

21000253405 is a deficient number, since it is larger than the sum of its proper divisors (5526382595).

21000253405 is a wasteful number, since it uses less digits than its factorization.

21000253405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 221055323.

The product of its (nonzero) digits is 1200, while the sum is 22.

Adding to 21000253405 its reverse (50435200012), we get a palindrome (71435453417).

The spelling of 21000253405 in words is "twenty-one billion, two hundred fifty-three thousand, four hundred five".