1975681 has 4 divisors (see below), whose sum is σ = 2013012. Its totient is φ = 1938352.

The previous prime is 1975669. The next prime is 1975691. The reversal of 1975681 is 1865791.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 497025 + 1478656 = 705^2 + 1216^2 .

It is a cyclic number.

It is not a de Polignac number, because 1975681 - 2¹¹ = 1973633 is a prime.

It is a super-2 number, since 2×1975681² = 7806630827522, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1975681.

It is not an unprimeable number, because it can be changed into a prime (1975651) 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, 18586 + ... + 18691.

It is an arithmetic number, because the mean of its divisors is an integer number (503253).

2^1975681 is an apocalyptic number.

It is an amenable number.

1975681 is a deficient number, since it is larger than the sum of its proper divisors (37331).

1975681 is an equidigital number, since it uses as much as digits as its factorization.

1975681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37330.

The product of its digits is 15120, while the sum is 37.

The square root of 1975681 is about 1405.5892003000. The cubic root of 1975681 is about 125.4793540743.

The spelling of 1975681 in words is "one million, nine hundred seventy-five thousand, six hundred eighty-one".