78661761 has 8 divisors (see below), whose sum is σ = 104936640. Its totient is φ = 52414032.

The previous prime is 78661727. The next prime is 78661763. The reversal of 78661761 is 16716687.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 78661761 - 2⁶ = 78661697 is a prime.

It is a super-2 number, since 2×78661761² = 12375345287242242, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (78661763) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1380 + ... + 12618.

It is an arithmetic number, because the mean of its divisors is an integer number (13117080).

Almost surely, 2^78661761 is an apocalyptic number.

It is an amenable number.

78661761 is a deficient number, since it is larger than the sum of its proper divisors (26274879).

78661761 is a wasteful number, since it uses less digits than its factorization.

78661761 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13575.

The product of its digits is 84672, while the sum is 42.

The square root of 78661761 is about 8869.1465767570. The cubic root of 78661761 is about 428.4707913067.

The spelling of 78661761 in words is "seventy-eight million, six hundred sixty-one thousand, seven hundred sixty-one".