21810742174451 has 4 divisors (see below), whose sum is σ = 21811237253400. Its totient is φ = 21810247095504.

The previous prime is 21810742174411. The next prime is 21810742174469. The reversal of 21810742174451 is 15447124701812.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21810742174451 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21810742174396 and 21810742174405.

It is not an unprimeable number, because it can be changed into a prime (21810742174411) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 247473386 + ... + 247561503.

It is an arithmetic number, because the mean of its divisors is an integer number (5452809313350).

Almost surely, 2^{21810742174451} is an apocalyptic number.

21810742174451 is a deficient number, since it is larger than the sum of its proper divisors (495078949).

21810742174451 is an equidigital number, since it uses as much as digits as its factorization.

21810742174451 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 495078948.

The product of its (nonzero) digits is 501760, while the sum is 47.

The spelling of 21810742174451 in words is "twenty-one trillion, eight hundred ten billion, seven hundred forty-two million, one hundred seventy-four thousand, four hundred fifty-one".