21253205344406 has 32 divisors (see below), whose sum is σ = 36722263818240. Its totient is φ = 9036472336416.

The previous prime is 21253205344381. The next prime is 21253205344457. The reversal of 21253205344406 is 60444350235212.

It is a super-2 number, since 2×21253205344406² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 53192531 + ... + 53590593.

It is an arithmetic number, because the mean of its divisors is an integer number (1147570744320).

Almost surely, 2^{21253205344406} is an apocalyptic number.

21253205344406 is a deficient number, since it is larger than the sum of its proper divisors (15469058473834).

21253205344406 is a wasteful number, since it uses less digits than its factorization.

21253205344406 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 428228.

The product of its (nonzero) digits is 691200, while the sum is 41.

Adding to 21253205344406 its reverse (60444350235212), we get a palindrome (81697555579618).

The spelling of 21253205344406 in words is "twenty-one trillion, two hundred fifty-three billion, two hundred five million, three hundred forty-four thousand, four hundred six".