665616445 has 16 divisors (see below), whose sum is σ = 874287792. Its totient is φ = 483471360.

The previous prime is 665616359. The next prime is 665616461. The reversal of 665616445 is 544616566.

It can be written as a sum of positive squares in 8 ways, for example, as 281534841 + 384081604 = 16779^2 + 19598^2 .

It is not a de Polignac number, because 665616445 - 2¹³ = 665608253 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 79972 + ... + 87901.

It is an arithmetic number, because the mean of its divisors is an integer number (54642987).

Almost surely, 2^665616445 is an apocalyptic number.

665616445 is a gapful number since it is divisible by the number (65) formed by its first and last digit.

It is an amenable number.

665616445 is a deficient number, since it is larger than the sum of its proper divisors (208671347).

665616445 is a wasteful number, since it uses less digits than its factorization.

665616445 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 167952.

The product of its digits is 518400, while the sum is 43.

The square root of 665616445 is about 25799.5435037134. The cubic root of 665616445 is about 873.1214970772.

The spelling of 665616445 in words is "six hundred sixty-five million, six hundred sixteen thousand, four hundred forty-five".