661445 has 8 divisors (see below), whose sum is σ = 798336. Its totient is φ = 526096.

The previous prime is 661439. The next prime is 661459. The reversal of 661445 is 544166.

It is a happy number.

661445 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 661445 - 2⁸ = 661189 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 7 ways as a sum of consecutive naturals, for example, 1064 + ... + 1566.

It is an arithmetic number, because the mean of its divisors is an integer number (99792).

2⁶⁶¹⁴⁴⁵ is an apocalyptic number.

It is an amenable number.

661445 is a deficient number, since it is larger than the sum of its proper divisors (136891).

661445 is a wasteful number, since it uses less digits than its factorization.

661445 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 771.

The product of its digits is 2880, while the sum is 26.

The square root of 661445 is about 813.2926902413. The cubic root of 661445 is about 87.1293710974.

The spelling of 661445 in words is "six hundred sixty-one thousand, four hundred forty-five".