61816117778 has 4 divisors (see below), whose sum is σ = 92724176670. Its totient is φ = 30908058888.

The previous prime is 61816117771. The next prime is 61816117787. The reversal of 61816117778 is 87771161816.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 46728171889 + 15087945889 = 216167^2 + 122833^2 .

It is a super-3 number, since 3×61816117778³ (a number of 33 digits) contains 333 as substring.

It is not an unprimeable number, because it can be changed into a prime (61816117771) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15454029443 + ... + 15454029446.

Almost surely, 2^61816117778 is an apocalyptic number.

61816117778 is a deficient number, since it is larger than the sum of its proper divisors (30908058892).

61816117778 is a wasteful number, since it uses less digits than its factorization.

61816117778 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30908058891.

The product of its digits is 790272, while the sum is 53.

The spelling of 61816117778 in words is "sixty-one billion, eight hundred sixteen million, one hundred seventeen thousand, seven hundred seventy-eight".