21227413645 has 4 divisors (see below), whose sum is σ = 25472896380. Its totient is φ = 16981930912.

The previous prime is 21227413631. The next prime is 21227413657. The reversal of 21227413645 is 54631472212.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 12854797641 + 8372616004 = 113379^2 + 91502^2 .

It is a cyclic number.

It is not a de Polignac number, because 21227413645 - 2⁹ = 21227413133 is a prime.

It is a super-3 number, since 3×21227413645³ (a number of 32 digits) contains 333 as substring.

It is a congruent number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 2122741360 + ... + 2122741369.

It is an arithmetic number, because the mean of its divisors is an integer number (6368224095).

Almost surely, 2^21227413645 is an apocalyptic number.

It is an amenable number.

21227413645 is a deficient number, since it is larger than the sum of its proper divisors (4245482735).

21227413645 is an equidigital number, since it uses as much as digits as its factorization.

21227413645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4245482734.

The product of its digits is 80640, while the sum is 37.

Adding to 21227413645 its reverse (54631472212), we get a palindrome (75858885857).

The spelling of 21227413645 in words is "twenty-one billion, two hundred twenty-seven million, four hundred thirteen thousand, six hundred forty-five".