21240144031 has 4 divisors (see below), whose sum is σ = 21246115600. Its totient is φ = 21234172464.

The previous prime is 21240144001. The next prime is 21240144041. The reversal of 21240144031 is 13044104212.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21240144031 - 2⁵ = 21240143999 is a prime.

It is a super-2 number, since 2×21240144031² (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 = 21240143993 and 21240144011.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21240144001) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2980446 + ... + 2987563.

It is an arithmetic number, because the mean of its divisors is an integer number (5311528900).

Almost surely, 2^21240144031 is an apocalyptic number.

21240144031 is a deficient number, since it is larger than the sum of its proper divisors (5971569).

21240144031 is an equidigital number, since it uses as much as digits as its factorization.

21240144031 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5971568.

The product of its (nonzero) digits is 768, while the sum is 22.

Adding to 21240144031 its reverse (13044104212), we get a palindrome (34284248243).

The spelling of 21240144031 in words is "twenty-one billion, two hundred forty million, one hundred forty-four thousand, thirty-one".