21400246405 has 16 divisors (see below), whose sum is σ = 26045867520. Its totient is φ = 16877158272.

The previous prime is 21400246397. The next prime is 21400246451. The reversal of 21400246405 is 50464200412.

It is a cyclic number.

It is not a de Polignac number, because 21400246405 - 2³ = 21400246397 is a prime.

It is a congruent number.

It is an unprimeable number.

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, 213697 + ... + 297433.

It is an arithmetic number, because the mean of its divisors is an integer number (1627866720).

Almost surely, 2^21400246405 is an apocalyptic number.

It is an amenable number.

21400246405 is a deficient number, since it is larger than the sum of its proper divisors (4645621115).

21400246405 is an equidigital number, since it uses as much as digits as its factorization.

21400246405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 84468.

The product of its (nonzero) digits is 7680, while the sum is 28.

Adding to 21400246405 its reverse (50464200412), we get a palindrome (71864446817).

The spelling of 21400246405 in words is "twenty-one billion, four hundred million, two hundred forty-six thousand, four hundred five".