1665961 has 4 divisors (see below), whose sum is σ = 1817424. Its totient is φ = 1514500.

The previous prime is 1665943. The next prime is 1665967. The reversal of 1665961 is 1695661.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1665961 - 2⁵ = 1665929 is a prime.

It is a Duffinian number.

1665961 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (1665967) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 75715 + ... + 75736.

It is an arithmetic number, because the mean of its divisors is an integer number (454356).

2^1665961 is an apocalyptic number.

1665961 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1665961 is a deficient number, since it is larger than the sum of its proper divisors (151463).

1665961 is a wasteful number, since it uses less digits than its factorization.

1665961 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 151462.

The product of its digits is 9720, while the sum is 34.

The square root of 1665961 is about 1290.7211162757. The cubic root of 1665961 is about 118.5463745806.

The spelling of 1665961 in words is "one million, six hundred sixty-five thousand, nine hundred sixty-one".