21557224545 has 16 divisors (see below), whose sum is σ = 34494532992. Its totient is φ = 11496195200.

The previous prime is 21557224543. The next prime is 21557224547. The reversal of 21557224545 is 54542275512.

It is an interprime number because it is at equal distance from previous prime (21557224543) and next prime (21557224547).

It is not a de Polignac number, because 21557224545 - 2¹ = 21557224543 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21557224497 and 21557224506.

It is not an unprimeable number, because it can be changed into a prime (21557224543) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 138820 + ... + 249770.

It is an arithmetic number, because the mean of its divisors is an integer number (2155908312).

Almost surely, 2^21557224545 is an apocalyptic number.

It is an amenable number.

21557224545 is a deficient number, since it is larger than the sum of its proper divisors (12937308447).

21557224545 is a wasteful number, since it uses less digits than its factorization.

21557224545 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 123912.

The product of its digits is 560000, while the sum is 42.

The spelling of 21557224545 in words is "twenty-one billion, five hundred fifty-seven million, two hundred twenty-four thousand, five hundred forty-five".