1867661 has 4 divisors (see below), whose sum is σ = 1877532. Its totient is φ = 1857792.

The previous prime is 1867651. The next prime is 1867693. The reversal of 1867661 is 1667681.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1667681 = 1117 ⋅1493.

It can be written as a sum of positive squares in 2 ways, for example, as 855625 + 1012036 = 925^2 + 1006^2 .

It is a cyclic number.

It is not a de Polignac number, because 1867661 - 2⁶ = 1867597 is a prime.

It is a super-2 number, since 2×1867661² = 6976315221842, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1867601) 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, 4646 + ... + 5031.

It is an arithmetic number, because the mean of its divisors is an integer number (469383).

2^1867661 is an apocalyptic number.

It is an amenable number.

1867661 is a deficient number, since it is larger than the sum of its proper divisors (9871).

1867661 is an equidigital number, since it uses as much as digits as its factorization.

1867661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9870.

The product of its digits is 12096, while the sum is 35.

The square root of 1867661 is about 1366.6239424216. The cubic root of 1867661 is about 123.1495086360.

The spelling of 1867661 in words is "one million, eight hundred sixty-seven thousand, six hundred sixty-one".