791921778 has 16 divisors (see below), whose sum is σ = 1677011040. Its totient is φ = 248446016.

The previous prime is 791921773. The next prime is 791921789. The reversal of 791921778 is 877129197.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (51).

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 791921778.

It is not an unprimeable number, because it can be changed into a prime (791921771) 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, 3881868 + ... + 3882071.

It is an arithmetic number, because the mean of its divisors is an integer number (104813190).

Almost surely, 2^791921778 is an apocalyptic number.

791921778 is an abundant number, since it is smaller than the sum of its proper divisors (885089262).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

791921778 is a wasteful number, since it uses less digits than its factorization.

791921778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7763961.

The product of its digits is 444528, while the sum is 51.

The square root of 791921778 is about 28141.1047757546. The cubic root of 791921778 is about 925.1825412329.

The spelling of 791921778 in words is "seven hundred ninety-one million, nine hundred twenty-one thousand, seven hundred seventy-eight".