81245030381 has 2 divisors, whose sum is σ = 81245030382. Its totient is φ = 81245030380.

The previous prime is 81245030311. The next prime is 81245030407. The reversal of 81245030381 is 18303054218.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 80863453225 + 381577156 = 284365^2 + 19534^2 .

It is a cyclic number.

It is not a de Polignac number, because 81245030381 - 2¹⁰ = 81245029357 is a prime.

It is a super-2 number, since 2×81245030381² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81245030311) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40622515190 + 40622515191.

It is an arithmetic number, because the mean of its divisors is an integer number (40622515191).

Almost surely, 2^81245030381 is an apocalyptic number.

It is an amenable number.

81245030381 is a deficient number, since it is larger than the sum of its proper divisors (1).

81245030381 is an equidigital number, since it uses as much as digits as its factorization.

81245030381 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 23040, while the sum is 35.

Adding to 81245030381 its reverse (18303054218), we get a palindrome (99548084599).

The spelling of 81245030381 in words is "eighty-one billion, two hundred forty-five million, thirty thousand, three hundred eighty-one".