1687401 has 9 divisors (see below), whose sum is σ = 2442999. Its totient is φ = 1122336.

The previous prime is 1687393. The next prime is 1687421. The reversal of 1687401 is 1047861.

It is a happy number.

The square root of 1687401 is 1299.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 189225 + 1498176 = 435^2 + 1224^2 .

It is a tau number, because it is divible by the number of its divisors (9).

It is not a de Polignac number, because 1687401 - 2³ = 1687393 is a prime.

It is an Ulam number.

It is a Curzon number.

1687401 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (1687421) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 3681 + ... + 4113.

2^1687401 is an apocalyptic number.

1687401 is the 1299-th square number.

1687401 is the 650-th centered octagonal number.

It is an amenable number.

1687401 is a deficient number, since it is larger than the sum of its proper divisors (755598).

1687401 is an frugal number, since it uses more digits than its factorization.

1687401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 872 (or 436 counting only the distinct ones).

The product of its (nonzero) digits is 1344, while the sum is 27.

The cubic root of 1687401 is about 119.0527506639.

It can be divided in two parts, 168 and 7401, that added together give a square (7569 = 87²).

The spelling of 1687401 in words is "one million, six hundred eighty-seven thousand, four hundred one".