21203105404511 has 16 divisors (see below), whose sum is σ = 23224822080768. Its totient is φ = 19270234329600.

The previous prime is 21203105404501. The next prime is 21203105404541. The reversal of 21203105404511 is 11540450130212.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 21203105404511 - 2⁴² = 16805058893407 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21203105404501) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 43394360 + ... + 43880253.

It is an arithmetic number, because the mean of its divisors is an integer number (1451551380048).

Almost surely, 2^{21203105404511} is an apocalyptic number.

21203105404511 is a deficient number, since it is larger than the sum of its proper divisors (2021716676257).

21203105404511 is a wasteful number, since it uses less digits than its factorization.

21203105404511 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 87275122.

The product of its (nonzero) digits is 4800, while the sum is 29.

Adding to 21203105404511 its reverse (11540450130212), we get a palindrome (32743555534723).

The spelling of 21203105404511 in words is "twenty-one trillion, two hundred three billion, one hundred five million, four hundred four thousand, five hundred eleven".