7778920 has 32 divisors (see below), whose sum is σ = 17667720. Its totient is φ = 3082240.

The previous prime is 7778891. The next prime is 7778921. The reversal of 7778920 is 298777.

It can be written as a sum of positive squares in 4 ways, for example, as 4813636 + 2965284 = 2194^2 + 1722^2 .

It is a Harshad number since it is a multiple of its sum of digits (40).

It is not an unprimeable number, because it can be changed into a prime (7778921) 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, 3660 + ... + 5380.

Almost surely, 2^7778920 is an apocalyptic number.

It is an amenable number.

7778920 is an abundant number, since it is smaller than the sum of its proper divisors (9888800).

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

7778920 is a wasteful number, since it uses less digits than its factorization.

7778920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1845 (or 1841 counting only the distinct ones).

The product of its (nonzero) digits is 49392, while the sum is 40.

The square root of 7778920 is about 2789.0715300974. The cubic root of 7778920 is about 198.1404302551.

The spelling of 7778920 in words is "seven million, seven hundred seventy-eight thousand, nine hundred twenty".