21451364365381 has 2 divisors, whose sum is σ = 21451364365382. Its totient is φ = 21451364365380.

The previous prime is 21451364365177. The next prime is 21451364365421. The reversal of 21451364365381 is 18356346315412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20231698137156 + 1219666228225 = 4497966^2 + 1104385^2 .

It is a cyclic number.

It is not a de Polignac number, because 21451364365381 - 2³³ = 21442774430789 is a prime.

It is a super-2 number, since 2×21451364365381² (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 (21451364360381) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10725682182690 + 10725682182691.

It is an arithmetic number, because the mean of its divisors is an integer number (10725682182691).

Almost surely, 2^{21451364365381} is an apocalyptic number.

It is an amenable number.

21451364365381 is a deficient number, since it is larger than the sum of its proper divisors (1).

21451364365381 is an equidigital number, since it uses as much as digits as its factorization.

21451364365381 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6220800, while the sum is 52.

The spelling of 21451364365381 in words is "twenty-one trillion, four hundred fifty-one billion, three hundred sixty-four million, three hundred sixty-five thousand, three hundred eighty-one".