665428221370 has 64 divisors (see below), whose sum is σ = 1347522324480. Its totient is φ = 234522164800.

The previous prime is 665428221251. The next prime is 665428221371. The reversal of 665428221370 is 73122824566.

It is a self number, because there is not a number n which added to its sum of digits gives 665428221370.

It is not an unprimeable number, because it can be changed into a prime (665428221371) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 261262 + ... + 1182841.

It is an arithmetic number, because the mean of its divisors is an integer number (21055036320).

Almost surely, 2^665428221370 is an apocalyptic number.

665428221370 is an abundant number, since it is smaller than the sum of its proper divisors (682094103110).

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

665428221370 is a wasteful number, since it uses less digits than its factorization.

665428221370 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1444251.

The product of its (nonzero) digits is 967680, while the sum is 46.

The spelling of 665428221370 in words is "six hundred sixty-five billion, four hundred twenty-eight million, two hundred twenty-one thousand, three hundred seventy".