21365701173451 has 2 divisors, whose sum is σ = 21365701173452. Its totient is φ = 21365701173450.

The previous prime is 21365701173449. The next prime is 21365701173473. The reversal of 21365701173451 is 15437110756312.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21365701173451 - 2¹ = 21365701173449 is a prime.

Together with 21365701173449, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (21365701173491) 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 as a sum of consecutive naturals, namely, 10682850586725 + 10682850586726.

It is an arithmetic number, because the mean of its divisors is an integer number (10682850586726).

Almost surely, 2^{21365701173451} is an apocalyptic number.

21365701173451 is a deficient number, since it is larger than the sum of its proper divisors (1).

21365701173451 is an equidigital number, since it uses as much as digits as its factorization.

21365701173451 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 529200, while the sum is 46.

The spelling of 21365701173451 in words is "twenty-one trillion, three hundred sixty-five billion, seven hundred one million, one hundred seventy-three thousand, four hundred fifty-one".