1891261 has 4 divisors (see below), whose sum is σ = 1899612. Its totient is φ = 1882912.

The previous prime is 1891249. The next prime is 1891273. The reversal of 1891261 is 1621981.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1621981 = 337 ⋅4813.

It is an interprime number because it is at equal distance from previous prime (1891249) and next prime (1891273).

It can be written as a sum of positive squares in 2 ways, for example, as 1092025 + 799236 = 1045^2 + 894^2 .

It is a cyclic number.

It is not a de Polignac number, because 1891261 - 2⁷ = 1891133 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 (1891291) 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, 3826 + ... + 4291.

It is an arithmetic number, because the mean of its divisors is an integer number (474903).

2^1891261 is an apocalyptic number.

It is an amenable number.

1891261 is a deficient number, since it is larger than the sum of its proper divisors (8351).

1891261 is an equidigital number, since it uses as much as digits as its factorization.

1891261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8350.

The product of its digits is 864, while the sum is 28.

The square root of 1891261 is about 1375.2312532807. The cubic root of 1891261 is about 123.6660499223. Note that the first 3 decimals are identical.

The spelling of 1891261 in words is "one million, eight hundred ninety-one thousand, two hundred sixty-one".