21254620605 has 16 divisors (see below), whose sum is σ = 34017456384. Its totient is φ = 11332443200.

The previous prime is 21254620601. The next prime is 21254620631. The reversal of 21254620605 is 50602645212.

It is not a de Polignac number, because 21254620605 - 2² = 21254620601 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21254620601) 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 15 ways as a sum of consecutive naturals, for example, 156846 + ... + 259055.

It is an arithmetic number, because the mean of its divisors is an integer number (2126091024).

Almost surely, 2^21254620605 is an apocalyptic number.

It is an amenable number.

21254620605 is a deficient number, since it is larger than the sum of its proper divisors (12762835779).

21254620605 is a wasteful number, since it uses less digits than its factorization.

21254620605 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 419316.

The product of its (nonzero) digits is 28800, while the sum is 33.

The spelling of 21254620605 in words is "twenty-one billion, two hundred fifty-four million, six hundred twenty thousand, six hundred five".