21204231001405 has 16 divisors (see below), whose sum is σ = 26941962507264. Its totient is φ = 15965469861120.

The previous prime is 21204231001399. The next prime is 21204231001409. The reversal of 21204231001405 is 50410013240212.

It is not a de Polignac number, because 21204231001405 - 2³ = 21204231001397 is a prime.

It is a super-2 number, since 2×21204231001405² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21204231001405.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21204231001409) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 28466260 + ... + 29201650.

It is an arithmetic number, because the mean of its divisors is an integer number (1683872656704).

Almost surely, 2^{21204231001405} is an apocalyptic number.

It is an amenable number.

21204231001405 is a deficient number, since it is larger than the sum of its proper divisors (5737731505859).

21204231001405 is a wasteful number, since it uses less digits than its factorization.

21204231001405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1074636.

The product of its (nonzero) digits is 1920, while the sum is 25.

Adding to 21204231001405 its reverse (50410013240212), we get a palindrome (71614244241617).

The spelling of 21204231001405 in words is "twenty-one trillion, two hundred four billion, two hundred thirty-one million, one thousand, four hundred five".