78990861 has 8 divisors (see below), whose sum is σ = 105851200. Its totient is φ = 52395552.

The previous prime is 78990859. The next prime is 78990881. The reversal of 78990861 is 16809987.

It is a happy number.

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

It is not a de Polignac number, because 78990861 - 2¹ = 78990859 is a prime.

It is a super-2 number, since 2×78990861² = 12479112243042642, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 78990861.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78990811) 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, 65560 + ... + 66753.

It is an arithmetic number, because the mean of its divisors is an integer number (13231400).

Almost surely, 2^78990861 is an apocalyptic number.

It is an amenable number.

78990861 is a deficient number, since it is larger than the sum of its proper divisors (26860339).

78990861 is a wasteful number, since it uses less digits than its factorization.

78990861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 132515.

The product of its (nonzero) digits is 217728, while the sum is 48.

The square root of 78990861 is about 8887.6802935299. The cubic root of 78990861 is about 429.0674960769.

The spelling of 78990861 in words is "seventy-eight million, nine hundred ninety thousand, eight hundred sixty-one".