1661378 has 8 divisors (see below), whose sum is σ = 2515260. Its totient is φ = 822960.

The previous prime is 1661353. The next prime is 1661431. The reversal of 1661378 is 8731661.

It can be written as a sum of positive squares in 2 ways, for example, as 1495729 + 165649 = 1223^2 + 407^2 .

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

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3593 + ... + 4028.

2^1661378 is an apocalyptic number.

1661378 is a deficient number, since it is larger than the sum of its proper divisors (853882).

1661378 is a wasteful number, since it uses less digits than its factorization.

1661378 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7732.

The product of its digits is 6048, while the sum is 32.

The square root of 1661378 is about 1288.9445294504. The cubic root of 1661378 is about 118.4375691132.

The spelling of 1661378 in words is "one million, six hundred sixty-one thousand, three hundred seventy-eight".