78161761 has 4 divisors (see below), whose sum is σ = 78853572. Its totient is φ = 77469952.

The previous prime is 78161737. The next prime is 78161789. The reversal of 78161761 is 16716187.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 16716187 = 1303 ⋅12829.

It can be written as a sum of positive squares in 2 ways, for example, as 21911761 + 56250000 = 4681^2 + 7500^2 .

It is a cyclic number.

It is not a de Polignac number, because 78161761 - 2⁹ = 78161249 is a prime.

It is a super-3 number, since 3×78161761³ (a number of 25 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 78161761.

It is not an unprimeable number, because it can be changed into a prime (78161701) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 345736 + ... + 345961.

It is an arithmetic number, because the mean of its divisors is an integer number (19713393).

Almost surely, 2^78161761 is an apocalyptic number.

It is an amenable number.

78161761 is a deficient number, since it is larger than the sum of its proper divisors (691811).

78161761 is a wasteful number, since it uses less digits than its factorization.

78161761 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 691810.

The product of its digits is 14112, while the sum is 37.

The square root of 78161761 is about 8840.9140364557. The cubic root of 78161761 is about 427.5610272760.

The spelling of 78161761 in words is "seventy-eight million, one hundred sixty-one thousand, seven hundred sixty-one".