21403243444 has 24 divisors (see below), whose sum is σ = 40963694688. Its totient is φ = 9704233440.

The previous prime is 21403243441. The next prime is 21403243447. The reversal of 21403243444 is 44434230412.

It is an interprime number because it is at equal distance from previous prime (21403243441) and next prime (21403243447).

It is a super-2 number, since 2×21403243444² (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 (21403243441) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 595174 + ... + 630109.

It is an arithmetic number, because the mean of its divisors is an integer number (1706820612).

Almost surely, 2^21403243444 is an apocalyptic number.

It is an amenable number.

21403243444 is a deficient number, since it is larger than the sum of its proper divisors (19560451244).

21403243444 is a wasteful number, since it uses less digits than its factorization.

21403243444 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1225695 (or 1225693 counting only the distinct ones).

The product of its (nonzero) digits is 36864, while the sum is 31.

Adding to 21403243444 its reverse (44434230412), we get a palindrome (65837473856).

The spelling of 21403243444 in words is "twenty-one billion, four hundred three million, two hundred forty-three thousand, four hundred forty-four".