117615781 has 2 divisors, whose sum is σ = 117615782. Its totient is φ = 117615780.

The previous prime is 117615779. The next prime is 117615811. The reversal of 117615781 is 187516711.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 108368100 + 9247681 = 10410^2 + 3041^2 .

It is an emirp because it is prime and its reverse (187516711) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 117615781 - 2¹ = 117615779 is a prime.

It is a super-2 number, since 2×117615781² = 27666943880479922, which contains 22 as substring.

Together with 117615779, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 117615781.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (117615481) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 58807890 + 58807891.

It is an arithmetic number, because the mean of its divisors is an integer number (58807891).

Almost surely, 2^117615781 is an apocalyptic number.

It is an amenable number.

117615781 is a deficient number, since it is larger than the sum of its proper divisors (1).

117615781 is an equidigital number, since it uses as much as digits as its factorization.

117615781 is an evil number, because the sum of its binary digits is even.

The product of its digits is 11760, while the sum is 37.

The square root of 117615781 is about 10845.0809586651. The cubic root of 117615781 is about 489.9538773747.

The spelling of 117615781 in words is "one hundred seventeen million, six hundred fifteen thousand, seven hundred eighty-one".