1958666 has 4 divisors (see below), whose sum is σ = 2938002. Its totient is φ = 979332.

The previous prime is 1958651. The next prime is 1958681. The reversal of 1958666 is 6668591.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 6668591 = 2269 ⋅2939.

It is an interprime number because it is at equal distance from previous prime (1958651) and next prime (1958681).

It can be written as a sum of positive squares in only one way, i.e., 1729225 + 229441 = 1315^2 + 479^2 .

It is an unprimeable number.

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, 489665 + ... + 489668.

2^1958666 is an apocalyptic number.

1958666 is a deficient number, since it is larger than the sum of its proper divisors (979336).

1958666 is an equidigital number, since it uses as much as digits as its factorization.

1958666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 979335.

The product of its digits is 77760, while the sum is 41.

The square root of 1958666 is about 1399.5234903352. The cubic root of 1958666 is about 125.1180963908.

It can be divided in two parts, 19 and 58666, that added together give a palindrome (58685).

The spelling of 1958666 in words is "one million, nine hundred fifty-eight thousand, six hundred sixty-six".