21404402431 has 16 divisors (see below), whose sum is σ = 22365088480. Its totient is φ = 20465343360.

The previous prime is 21404402419. The next prime is 21404402441. The reversal of 21404402431 is 13420440412.

It is a cyclic number.

It is not a de Polignac number, because 21404402431 - 2¹⁵ = 21404369663 is a prime.

It is a super-2 number, since 2×21404402431² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21404402396 and 21404402405.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21404402401) 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, 1033405 + ... + 1053913.

It is an arithmetic number, because the mean of its divisors is an integer number (1397818030).

Almost surely, 2^21404402431 is an apocalyptic number.

21404402431 is a deficient number, since it is larger than the sum of its proper divisors (960686049).

21404402431 is a wasteful number, since it uses less digits than its factorization.

21404402431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21034.

The product of its (nonzero) digits is 3072, while the sum is 25.

Adding to 21404402431 its reverse (13420440412), we get a palindrome (34824842843).

The spelling of 21404402431 in words is "twenty-one billion, four hundred four million, four hundred two thousand, four hundred thirty-one".