21072866192381 has 2 divisors, whose sum is σ = 21072866192382. Its totient is φ = 21072866192380.

The previous prime is 21072866192347. The next prime is 21072866192449. The reversal of 21072866192381 is 18329166827012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11731590869881 + 9341275322500 = 3425141^2 + 3056350^2 .

It is a cyclic number.

It is not a de Polignac number, because 21072866192381 - 2²² = 21072861998077 is a prime.

It is a super-2 number, since 2×21072866192381² (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 (21072866192881) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10536433096190 + 10536433096191.

It is an arithmetic number, because the mean of its divisors is an integer number (10536433096191).

Almost surely, 2^{21072866192381} is an apocalyptic number.

It is an amenable number.

21072866192381 is a deficient number, since it is larger than the sum of its proper divisors (1).

21072866192381 is an equidigital number, since it uses as much as digits as its factorization.

21072866192381 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3483648, while the sum is 56.

The spelling of 21072866192381 in words is "twenty-one trillion, seventy-two billion, eight hundred sixty-six million, one hundred ninety-two thousand, three hundred eighty-one".