78399961 has 8 divisors (see below), whose sum is σ = 81358848. Its totient is φ = 75468000.

The previous prime is 78399953. The next prime is 78399973. The reversal of 78399961 is 16999387.

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 78399961 - 2³ = 78399953 is a prime.

It is a super-2 number, since 2×78399961² = 12293107769603042, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 78399899 and 78399908.

It is not an unprimeable number, because it can be changed into a prime (78399941) 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, 700 + ... + 12541.

It is an arithmetic number, because the mean of its divisors is an integer number (10169856).

Almost surely, 2^78399961 is an apocalyptic number.

It is an amenable number.

78399961 is a deficient number, since it is larger than the sum of its proper divisors (2958887).

78399961 is a wasteful number, since it uses less digits than its factorization.

78399961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13463.

The product of its digits is 734832, while the sum is 52.

The square root of 78399961 is about 8854.3752461707. The cubic root of 78399961 is about 427.9949212575.

The spelling of 78399961 in words is "seventy-eight million, three hundred ninety-nine thousand, nine hundred sixty-one".