21400404421 has 8 divisors (see below), whose sum is σ = 23741589600. Its totient is φ = 19125168240.

The previous prime is 21400404419. The next prime is 21400404481. The reversal of 21400404421 is 12440400412.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21400404421 - 2¹ = 21400404419 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21400404392 and 21400404401.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21400404401) 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, 16486566 + ... + 16487863.

It is an arithmetic number, because the mean of its divisors is an integer number (2967698700).

Almost surely, 2^21400404421 is an apocalyptic number.

It is an amenable number.

21400404421 is a deficient number, since it is larger than the sum of its proper divisors (2341185179).

21400404421 is a wasteful number, since it uses less digits than its factorization.

21400404421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32974499.

The product of its (nonzero) digits is 1024, while the sum is 22.

Adding to 21400404421 its reverse (12440400412), we get a palindrome (33840804833).

The spelling of 21400404421 in words is "twenty-one billion, four hundred million, four hundred four thousand, four hundred twenty-one".