21244040421 has 16 divisors (see below), whose sum is σ = 28459034688. Its totient is φ = 14096016000.

The previous prime is 21244040401. The next prime is 21244040423. The reversal of 21244040421 is 12404044212.

It is not a de Polignac number, because 21244040421 - 2⁹ = 21244039909 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21244040391 and 21244040400.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21244040423) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 578995 + ... + 614591.

It is an arithmetic number, because the mean of its divisors is an integer number (1778689668).

Almost surely, 2^21244040421 is an apocalyptic number.

It is an amenable number.

21244040421 is a deficient number, since it is larger than the sum of its proper divisors (7214994267).

21244040421 is a wasteful number, since it uses less digits than its factorization.

21244040421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36532.

The product of its (nonzero) digits is 2048, while the sum is 24.

Adding to 21244040421 its reverse (12404044212), we get a palindrome (33648084633).

It can be divided in two parts, 21 and 244040421, that added together give a palindrome (244040442).

The spelling of 21244040421 in words is "twenty-one billion, two hundred forty-four million, forty thousand, four hundred twenty-one".