21404340265 has 64 divisors (see below), whose sum is σ = 33466245120. Its totient is φ = 12754909440.

The previous prime is 21404340187. The next prime is 21404340289. The reversal of 21404340265 is 56204340412.

It is not a de Polignac number, because 21404340265 - 2¹³ = 21404332073 is a prime.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 764331 + ... + 791839.

It is an arithmetic number, because the mean of its divisors is an integer number (522910080).

Almost surely, 2^21404340265 is an apocalyptic number.

It is an amenable number.

21404340265 is a deficient number, since it is larger than the sum of its proper divisors (12061904855).

21404340265 is a wasteful number, since it uses less digits than its factorization.

21404340265 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27622.

The product of its (nonzero) digits is 23040, while the sum is 31.

Adding to 21404340265 its reverse (56204340412), we get a palindrome (77608680677).

The spelling of 21404340265 in words is "twenty-one billion, four hundred four million, three hundred forty thousand, two hundred sixty-five".