78409961 has 8 divisors (see below), whose sum is σ = 89930304. Its totient is φ = 66969360.

The previous prime is 78409951. The next prime is 78409963. The reversal of 78409961 is 16990487.

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

It is a cyclic number.

It is not a de Polignac number, because 78409961 - 2¹⁴ = 78393577 is a prime.

It is a super-2 number, since 2×78409961² = 12296243968043042, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78409963) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 17810 + ... + 21771.

It is an arithmetic number, because the mean of its divisors is an integer number (11241288).

Almost surely, 2^78409961 is an apocalyptic number.

It is an amenable number.

78409961 is a deficient number, since it is larger than the sum of its proper divisors (11520343).

78409961 is a wasteful number, since it uses less digits than its factorization.

78409961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39871.

The product of its (nonzero) digits is 108864, while the sum is 44.

The square root of 78409961 is about 8854.9399207448. The cubic root of 78409961 is about 428.0131175559.

The spelling of 78409961 in words is "seventy-eight million, four hundred nine thousand, nine hundred sixty-one".