78390979 has 8 divisors (see below), whose sum is σ = 82599440. Its totient is φ = 74190816.

The previous prime is 78390953. The next prime is 78390997. The reversal of 78390979 is 97909387.

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 78390979 - 2²¹ = 76293827 is a prime.

It is a super-2 number, since 2×78390979² = 12290291177156882, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78390079) 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, 30949 + ... + 33385.

It is an arithmetic number, because the mean of its divisors is an integer number (10324930).

Almost surely, 2^78390979 is an apocalyptic number.

78390979 is a deficient number, since it is larger than the sum of its proper divisors (4208461).

78390979 is a wasteful number, since it uses less digits than its factorization.

78390979 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4149.

The product of its (nonzero) digits is 857304, while the sum is 52.

The square root of 78390979 is about 8853.8680247675. The cubic root of 78390979 is about 427.9785760231.

The spelling of 78390979 in words is "seventy-eight million, three hundred ninety thousand, nine hundred seventy-nine".