1671661 has 8 divisors (see below), whose sum is σ = 1788480. Its totient is φ = 1556928.

The previous prime is 1671643. The next prime is 1671671. The reversal of 1671661 is 1661761.

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

It is not a de Polignac number, because 1671661 - 2⁵ = 1671629 is a prime.

It is a super-3 number, since 3×1671661³ = 14014121746430333343, which contains 333 as substring.

It is an Ulam number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1671641) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1360 + ... + 2278.

It is an arithmetic number, because the mean of its divisors is an integer number (223560).

2^1671661 is an apocalyptic number.

It is an amenable number.

1671661 is a deficient number, since it is larger than the sum of its proper divisors (116819).

1671661 is a wasteful number, since it uses less digits than its factorization.

1671661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1043.

The product of its digits is 1512, while the sum is 28.

The square root of 1671661 is about 1292.9272988069. The cubic root of 1671661 is about 118.6814207903.

It can be divided in two parts, 1671 and 661, that added together give a palindrome (2332).

The spelling of 1671661 in words is "one million, six hundred seventy-one thousand, six hundred sixty-one".