81634028617 has 2 divisors, whose sum is σ = 81634028618. Its totient is φ = 81634028616.

The previous prime is 81634028563. The next prime is 81634028647. The reversal of 81634028617 is 71682043618.

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., 59541368121 + 22092660496 = 244011^2 + 148636^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81634028617 is a prime.

It is a super-3 number, since 3×81634028617³ (a number of 34 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is not a weakly prime, because it can be changed into another prime (81634028647) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40817014308 + 40817014309.

It is an arithmetic number, because the mean of its divisors is an integer number (40817014309).

Almost surely, 2^81634028617 is an apocalyptic number.

It is an amenable number.

81634028617 is a deficient number, since it is larger than the sum of its proper divisors (1).

81634028617 is an equidigital number, since it uses as much as digits as its factorization.

81634028617 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 387072, while the sum is 46.

The spelling of 81634028617 in words is "eighty-one billion, six hundred thirty-four million, twenty-eight thousand, six hundred seventeen".