21231035562551 has 16 divisors (see below), whose sum is σ = 21957622714368. Its totient is φ = 20507073847200.

The previous prime is 21231035562547. The next prime is 21231035562619. The reversal of 21231035562551 is 15526553013212.

It is not a de Polignac number, because 21231035562551 - 2² = 21231035562547 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21231035562499 and 21231035562508.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21231035562851) 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, 70674296 + ... + 70974066.

It is an arithmetic number, because the mean of its divisors is an integer number (1372351419648).

Almost surely, 2^{21231035562551} is an apocalyptic number.

21231035562551 is a deficient number, since it is larger than the sum of its proper divisors (726587151817).

21231035562551 is a wasteful number, since it uses less digits than its factorization.

21231035562551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 304142.

The product of its (nonzero) digits is 270000, while the sum is 41.

Adding to 21231035562551 its reverse (15526553013212), we get a palindrome (36757588575763).

The spelling of 21231035562551 in words is "twenty-one trillion, two hundred thirty-one billion, thirty-five million, five hundred sixty-two thousand, five hundred fifty-one".