21545162551 has 16 divisors (see below), whose sum is σ = 24985594368. Its totient is φ = 18360880000.

The previous prime is 21545162501. The next prime is 21545162557. The reversal of 21545162551 is 15526154512.

It is a cyclic number.

It is not a de Polignac number, because 21545162551 - 2⁹ = 21545162039 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21545162551.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21545162557) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 182575 + ... + 276448.

It is an arithmetic number, because the mean of its divisors is an integer number (1561599648).

Almost surely, 2^21545162551 is an apocalyptic number.

21545162551 is a deficient number, since it is larger than the sum of its proper divisors (3440431817).

21545162551 is a wasteful number, since it uses less digits than its factorization.

21545162551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 459302.

The product of its digits is 60000, while the sum is 37.

The spelling of 21545162551 in words is "twenty-one billion, five hundred forty-five million, one hundred sixty-two thousand, five hundred fifty-one".