1661672 has 8 divisors (see below), whose sum is σ = 3115650. Its totient is φ = 830832.

The previous prime is 1661669. The next prime is 1661677. The reversal of 1661672 is 2761661.

It can be written as a sum of positive squares in only one way, i.e., 1012036 + 649636 = 1006^2 + 806^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is a super-2 number, since 2×1661672² = 5522307671168, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1661677) 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 as a sum of consecutive naturals, namely, 103847 + ... + 103862.

2^1661672 is an apocalyptic number.

It is an amenable number.

1661672 is a deficient number, since it is larger than the sum of its proper divisors (1453978).

1661672 is a wasteful number, since it uses less digits than its factorization.

1661672 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 207715 (or 207711 counting only the distinct ones).

The product of its digits is 3024, while the sum is 29.

The square root of 1661672 is about 1289.0585712061. The cubic root of 1661672 is about 118.4445549992. Note that the first 3 decimals are identical.

The spelling of 1661672 in words is "one million, six hundred sixty-one thousand, six hundred seventy-two".