61117778461 has 2 divisors, whose sum is σ = 61117778462. Its totient is φ = 61117778460.

The previous prime is 61117778317. The next prime is 61117778473. The reversal of 61117778461 is 16487771116.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 58071842361 + 3045936100 = 240981^2 + 55190^2 .

It is a cyclic number.

It is not a de Polignac number, because 61117778461 - 2¹⁷ = 61117647389 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (61117775461) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30558889230 + 30558889231.

It is an arithmetic number, because the mean of its divisors is an integer number (30558889231).

Almost surely, 2^61117778461 is an apocalyptic number.

It is an amenable number.

61117778461 is a deficient number, since it is larger than the sum of its proper divisors (1).

61117778461 is an equidigital number, since it uses as much as digits as its factorization.

61117778461 is an evil number, because the sum of its binary digits is even.

The product of its digits is 395136, while the sum is 49.

The spelling of 61117778461 in words is "sixty-one billion, one hundred seventeen million, seven hundred seventy-eight thousand, four hundred sixty-one".