21400235625421 has 32 divisors (see below), whose sum is σ = 22777394365440. Its totient is φ = 20078769908736.

The previous prime is 21400235625403. The next prime is 21400235625469. The reversal of 21400235625421 is 12452653200412.

It is a cyclic number.

It is not a de Polignac number, because 21400235625421 - 2⁹ = 21400235624909 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (37).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21400235665421) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 122670585 + ... + 122844913.

It is an arithmetic number, because the mean of its divisors is an integer number (711793573920).

Almost surely, 2^{21400235625421} is an apocalyptic number.

It is an amenable number.

21400235625421 is a deficient number, since it is larger than the sum of its proper divisors (1377158740019).

21400235625421 is a wasteful number, since it uses less digits than its factorization.

21400235625421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 175453.

The product of its (nonzero) digits is 115200, while the sum is 37.

Adding to 21400235625421 its reverse (12452653200412), we get a palindrome (33852888825833).

The spelling of 21400235625421 in words is "twenty-one trillion, four hundred billion, two hundred thirty-five million, six hundred twenty-five thousand, four hundred twenty-one".