21431212144 has 20 divisors (see below), whose sum is σ = 42862425280. Its totient is φ = 10369941120.

The previous prime is 21431212133. The next prime is 21431212157. The reversal of 21431212144 is 44121213412.

21431212144 is an admirable number.

It is a super-2 number, since 2×21431212144² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21603549 + ... + 21604540.

It is an arithmetic number, because the mean of its divisors is an integer number (2143121264).

Almost surely, 2^21431212144 is an apocalyptic number.

It is an amenable number.

21431212144 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21431212144 is a wasteful number, since it uses less digits than its factorization.

21431212144 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43208128 (or 43208122 counting only the distinct ones).

The product of its digits is 1536, while the sum is 25.

Adding to 21431212144 its reverse (44121213412), we get a palindrome (65552425556).

The spelling of 21431212144 in words is "twenty-one billion, four hundred thirty-one million, two hundred twelve thousand, one hundred forty-four".