21401323444 has 12 divisors (see below), whose sum is σ = 37453792068. Its totient is φ = 10700240000.

The previous prime is 21401323441. The next prime is 21401323499. The reversal of 21401323444 is 44432310412.

It can be written as a sum of positive squares in 2 ways, for example, as 3319142544 + 18082180900 = 57612^2 + 134470^2 .

It is a super-2 number, since 2×21401323444² (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 (21401323441) 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, 27324 + ... + 208684.

It is an arithmetic number, because the mean of its divisors is an integer number (3121149339).

Almost surely, 2^21401323444 is an apocalyptic number.

It is an amenable number.

21401323444 is a deficient number, since it is larger than the sum of its proper divisors (16052468624).

21401323444 is a wasteful number, since it uses less digits than its factorization.

21401323444 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 210866 (or 210864 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 28.

Adding to 21401323444 its reverse (44432310412), we get a palindrome (65833633856).

The spelling of 21401323444 in words is "twenty-one billion, four hundred one million, three hundred twenty-three thousand, four hundred forty-four".