78549661 has 8 divisors (see below), whose sum is σ = 82473120. Its totient is φ = 74707248.

The previous prime is 78549637. The next prime is 78549701. The reversal of 78549661 is 16694587.

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

It is not a de Polignac number, because 78549661 - 2¹¹ = 78547613 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78549461) 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, 18271 + ... + 22156.

It is an arithmetic number, because the mean of its divisors is an integer number (10309140).

Almost surely, 2^78549661 is an apocalyptic number.

It is an amenable number.

78549661 is a deficient number, since it is larger than the sum of its proper divisors (3923459).

78549661 is a wasteful number, since it uses less digits than its factorization.

78549661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40523.

The product of its digits is 362880, while the sum is 46.

The square root of 78549661 is about 8862.8246626005. The cubic root of 78549661 is about 428.2671582259.

The spelling of 78549661 in words is "seventy-eight million, five hundred forty-nine thousand, six hundred sixty-one".