1661445 has 32 divisors (see below), whose sum is σ = 3056640. Its totient is φ = 855360.

The previous prime is 1661441. The next prime is 1661447. The reversal of 1661445 is 5441661.

1661445 is a `hidden beast` number, since 1 + 6 + 614 + 45 = 666.

It is not a de Polignac number, because 1661445 - 2² = 1661441 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1661441) 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, 3987 + ... + 4383.

It is an arithmetic number, because the mean of its divisors is an integer number (95520).

2^1661445 is an apocalyptic number.

1661445 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1661445 is a deficient number, since it is larger than the sum of its proper divisors (1395195).

1661445 is a wasteful number, since it uses less digits than its factorization.

1661445 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 442 (or 436 counting only the distinct ones).

The product of its digits is 2880, while the sum is 27.

The square root of 1661445 is about 1288.9705194457. The cubic root of 1661445 is about 118.4391612074.

The spelling of 1661445 in words is "one million, six hundred sixty-one thousand, four hundred forty-five".