21461201645381 has 2 divisors, whose sum is σ = 21461201645382. Its totient is φ = 21461201645380.

The previous prime is 21461201645327. The next prime is 21461201645419. The reversal of 21461201645381 is 18354610216412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18377897433025 + 3083304212356 = 4286945^2 + 1755934^2 .

It is a cyclic number.

It is not a de Polignac number, because 21461201645381 - 2²² = 21461197451077 is a prime.

It is a super-2 number, since 2×21461201645381² (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 (21461201645581) 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, 10730600822690 + 10730600822691.

It is an arithmetic number, because the mean of its divisors is an integer number (10730600822691).

Almost surely, 2^{21461201645381} is an apocalyptic number.

It is an amenable number.

21461201645381 is a deficient number, since it is larger than the sum of its proper divisors (1).

21461201645381 is an equidigital number, since it uses as much as digits as its factorization.

21461201645381 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 276480, while the sum is 44.

The spelling of 21461201645381 in words is "twenty-one trillion, four hundred sixty-one billion, two hundred one million, six hundred forty-five thousand, three hundred eighty-one".