21345440031 has 14 divisors (see below), whose sum is σ = 32003520920. Its totient is φ = 14230292868.

The previous prime is 21345440027. The next prime is 21345440087. The reversal of 21345440031 is 13004454312.

It is a happy number.

21345440031 is a `hidden beast` number, since 213 + 4 + 5 + 440 + 0 + 3 + 1 = 666.

It is not a de Polignac number, because 21345440031 - 2² = 21345440027 is a prime.

It is a super-2 number, since 2×21345440031² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21345439977 and 21345440004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21345240031) 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 13 ways as a sum of consecutive naturals, for example, 14639491 + ... + 14640948.

It is an arithmetic number, because the mean of its divisors is an integer number (2285965780).

Almost surely, 2^21345440031 is an apocalyptic number.

21345440031 is a deficient number, since it is larger than the sum of its proper divisors (10658080889).

21345440031 is an frugal number, since it uses more digits than its factorization.

21345440031 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29280457 (or 29280442 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 27.

Adding to 21345440031 its reverse (13004454312), we get a palindrome (34349894343).

The spelling of 21345440031 in words is "twenty-one billion, three hundred forty-five million, four hundred forty thousand, thirty-one".