21400701065 has 16 divisors (see below), whose sum is σ = 26111776656. Its totient is φ = 16833484800.

The previous prime is 21400701059. The next prime is 21400701067. The reversal of 21400701065 is 56010700412.

It can be written as a sum of positive squares in 8 ways, for example, as 649434256 + 20751266809 = 25484^2 + 144053^2 .

It is not a de Polignac number, because 21400701065 - 2⁶ = 21400701001 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21400701067) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 888785 + ... + 912545.

It is an arithmetic number, because the mean of its divisors is an integer number (1631986041).

Almost surely, 2^21400701065 is an apocalyptic number.

It is an amenable number.

21400701065 is a deficient number, since it is larger than the sum of its proper divisors (4711075591).

21400701065 is a wasteful number, since it uses less digits than its factorization.

21400701065 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26780.

The product of its (nonzero) digits is 1680, while the sum is 26.

The spelling of 21400701065 in words is "twenty-one billion, four hundred million, seven hundred one thousand, sixty-five".