21403440231 has 16 divisors (see below), whose sum is σ = 28991490528. Its totient is φ = 14043801600.

The previous prime is 21403440221. The next prime is 21403440251. The reversal of 21403440231 is 13204430412.

It is not a de Polignac number, because 21403440231 - 2⁶ = 21403440167 is a prime.

It is a super-2 number, since 2×21403440231² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21403440221) 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, 150510 + ... + 255851.

It is an arithmetic number, because the mean of its divisors is an integer number (1811968158).

Almost surely, 2^21403440231 is an apocalyptic number.

21403440231 is a deficient number, since it is larger than the sum of its proper divisors (7588050297).

21403440231 is a wasteful number, since it uses less digits than its factorization.

21403440231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 406642.

The product of its (nonzero) digits is 2304, while the sum is 24.

Adding to 21403440231 its reverse (13204430412), we get a palindrome (34607870643).

The spelling of 21403440231 in words is "twenty-one billion, four hundred three million, four hundred forty thousand, two hundred thirty-one".