669771780 has 96 divisors (see below), whose sum is σ = 2039458176. Its totient is φ = 163547136.

The previous prime is 669771779. The next prime is 669771811. The reversal of 669771780 is 87177966.

It is a happy number.

669771780 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 28867 + ... + 46613.

It is an arithmetic number, because the mean of its divisors is an integer number (21244356).

Almost surely, 2^669771780 is an apocalyptic number.

669771780 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 669771780, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1019729088).

669771780 is an abundant number, since it is smaller than the sum of its proper divisors (1369686396).

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

669771780 is a wasteful number, since it uses less digits than its factorization.

669771780 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17813 (or 17811 counting only the distinct ones).

The product of its (nonzero) digits is 889056, while the sum is 51.

The square root of 669771780 is about 25879.9493817125. The cubic root of 669771780 is about 874.9346476361.

The spelling of 669771780 in words is "six hundred sixty-nine million, seven hundred seventy-one thousand, seven hundred eighty".