21155003452381 has 2 divisors, whose sum is σ = 21155003452382. Its totient is φ = 21155003452380.

The previous prime is 21155003452139. The next prime is 21155003452489. The reversal of 21155003452381 is 18325430055112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21149007428025 + 5996024356 = 4598805^2 + 77434^2 .

It is a cyclic number.

It is not a de Polignac number, because 21155003452381 - 2³¹ = 21152855968733 is a prime.

It is a super-2 number, since 2×21155003452381² (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 (21155003462381) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10577501726190 + 10577501726191.

It is an arithmetic number, because the mean of its divisors is an integer number (10577501726191).

Almost surely, 2^{21155003452381} is an apocalyptic number.

It is an amenable number.

21155003452381 is a deficient number, since it is larger than the sum of its proper divisors (1).

21155003452381 is an equidigital number, since it uses as much as digits as its factorization.

21155003452381 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 144000, while the sum is 40.

The spelling of 21155003452381 in words is "twenty-one trillion, one hundred fifty-five billion, three million, four hundred fifty-two thousand, three hundred eighty-one".