1661959 has 4 divisors (see below), whose sum is σ = 1789816. Its totient is φ = 1534104.

The previous prime is 1661953. The next prime is 1661969. The reversal of 1661959 is 9591661.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 9591661 = 1171 ⋅8191.

It is not a de Polignac number, because 1661959 - 2⁷ = 1661831 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1661953) 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, 63909 + ... + 63934.

It is an arithmetic number, because the mean of its divisors is an integer number (447454).

2^1661959 is an apocalyptic number.

1661959 is a deficient number, since it is larger than the sum of its proper divisors (127857).

1661959 is a wasteful number, since it uses less digits than its factorization.

1661959 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 127856.

The product of its digits is 14580, while the sum is 37.

The square root of 1661959 is about 1289.1698879512. The cubic root of 1661959 is about 118.4513737597.

The spelling of 1661959 in words is "one million, six hundred sixty-one thousand, nine hundred fifty-nine".