21404345231 has 16 divisors (see below), whose sum is σ = 21774392640. Its totient is φ = 21037916160.

The previous prime is 21404345203. The next prime is 21404345233. The reversal of 21404345231 is 13254340412.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21404345231 is a prime.

It is a super-2 number, since 2×21404345231² (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 = 21404345194 and 21404345203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21404345233) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 14335721 + ... + 14337213.

It is an arithmetic number, because the mean of its divisors is an integer number (1360899540).

Almost surely, 2^21404345231 is an apocalyptic number.

21404345231 is a deficient number, since it is larger than the sum of its proper divisors (370047409).

21404345231 is a wasteful number, since it uses less digits than its factorization.

21404345231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2546.

The product of its (nonzero) digits is 11520, while the sum is 29.

Adding to 21404345231 its reverse (13254340412), we get a palindrome (34658685643).

The spelling of 21404345231 in words is "twenty-one billion, four hundred four million, three hundred forty-five thousand, two hundred thirty-one".