78968991 has 8 divisors (see below), whose sum is σ = 106734640. Its totient is φ = 51924672.

The previous prime is 78968951. The next prime is 78968999. The reversal of 78968991 is 19986987.

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

It is not a de Polignac number, because 78968991 - 2¹⁵ = 78936223 is a prime.

It is a super-2 number, since 2×78968991² = 12472203079116162, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78968999) 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, 180076 + ... + 180513.

It is an arithmetic number, because the mean of its divisors is an integer number (13341830).

Almost surely, 2^78968991 is an apocalyptic number.

78968991 is a deficient number, since it is larger than the sum of its proper divisors (27765649).

78968991 is a wasteful number, since it uses less digits than its factorization.

78968991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 360665.

The product of its digits is 1959552, while the sum is 57.

The square root of 78968991 is about 8886.4498535692. The cubic root of 78968991 is about 429.0278941442.

The spelling of 78968991 in words is "seventy-eight million, nine hundred sixty-eight thousand, nine hundred ninety-one".