21144432413 has 4 divisors (see below), whose sum is σ = 22770927228. Its totient is φ = 19517937600.

The previous prime is 21144432409. The next prime is 21144432433. The reversal of 21144432413 is 31423444112.

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

It can be written as a sum of positive squares in 2 ways, for example, as 4586404729 + 16558027684 = 67723^2 + 128678^2 .

It is a cyclic number.

It is not a de Polignac number, because 21144432413 - 2² = 21144432409 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21144432433) 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, 813247388 + ... + 813247413.

It is an arithmetic number, because the mean of its divisors is an integer number (5692731807).

Almost surely, 2^21144432413 is an apocalyptic number.

It is an amenable number.

21144432413 is a deficient number, since it is larger than the sum of its proper divisors (1626494815).

21144432413 is a wasteful number, since it uses less digits than its factorization.

21144432413 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1626494814.

The product of its digits is 9216, while the sum is 29.

Adding to 21144432413 its reverse (31423444112), we get a palindrome (52567876525).

The spelling of 21144432413 in words is "twenty-one billion, one hundred forty-four million, four hundred thirty-two thousand, four hundred thirteen".