21424427345 has 16 divisors (see below), whose sum is σ = 26031463248. Its totient is φ = 16925552640.

The previous prime is 21424427291. The next prime is 21424427377. The reversal of 21424427345 is 54372442412.

It can be written as a sum of positive squares in 8 ways, for example, as 2156766481 + 19267660864 = 46441^2 + 138808^2 .

It is not a de Polignac number, because 21424427345 - 2³⁰ = 20350685521 is a prime.

It is a super-2 number, since 2×21424427345² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21424427299 and 21424427308.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 173315 + ... + 269975.

It is an arithmetic number, because the mean of its divisors is an integer number (1626966453).

Almost surely, 2^21424427345 is an apocalyptic number.

It is an amenable number.

21424427345 is a deficient number, since it is larger than the sum of its proper divisors (4607035903).

21424427345 is an equidigital number, since it uses as much as digits as its factorization.

21424427345 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 97220.

The product of its digits is 215040, while the sum is 38.

Adding to 21424427345 its reverse (54372442412), we get a palindrome (75796869757).

The spelling of 21424427345 in words is "twenty-one billion, four hundred twenty-four million, four hundred twenty-seven thousand, three hundred forty-five".