21357172182727 has 2 divisors, whose sum is σ = 21357172182728. Its totient is φ = 21357172182726.

The previous prime is 21357172182673. The next prime is 21357172182757. The reversal of 21357172182727 is 72728127175312.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21357172182727 - 2¹⁹ = 21357171658439 is a prime.

It is a super-2 number, since 2×21357172182727² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21357172182757) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10678586091363 + 10678586091364.

It is an arithmetic number, because the mean of its divisors is an integer number (10678586091364).

Almost surely, 2^{21357172182727} is an apocalyptic number.

21357172182727 is a deficient number, since it is larger than the sum of its proper divisors (1).

21357172182727 is an equidigital number, since it uses as much as digits as its factorization.

21357172182727 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4609920, while the sum is 55.

The spelling of 21357172182727 in words is "twenty-one trillion, three hundred fifty-seven billion, one hundred seventy-two million, one hundred eighty-two thousand, seven hundred twenty-seven".