1851281 has 4 divisors (see below), whose sum is σ = 1864932. Its totient is φ = 1837632.

The previous prime is 1851271. The next prime is 1851287. The reversal of 1851281 is 1821581.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1821581 = 293 ⋅6217.

It can be written as a sum of positive squares in 2 ways, for example, as 1032256 + 819025 = 1016^2 + 905^2 .

It is a cyclic number.

It is not a de Polignac number, because 1851281 - 2⁶ = 1851217 is a prime.

It is a super-2 number, since 2×1851281² = 6854482681922, which contains 22 as substring.

It is an Ulam number.

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 1851281.

It is not an unprimeable number, because it can be changed into a prime (1851287) 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, 6620 + ... + 6893.

It is an arithmetic number, because the mean of its divisors is an integer number (466233).

2^1851281 is an apocalyptic number.

It is an amenable number.

1851281 is a deficient number, since it is larger than the sum of its proper divisors (13651).

1851281 is a wasteful number, since it uses less digits than its factorization.

1851281 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13650.

The product of its digits is 640, while the sum is 26.

The square root of 1851281 is about 1360.6178743497. The cubic root of 1851281 is about 122.7884304407.

The spelling of 1851281 in words is "one million, eight hundred fifty-one thousand, two hundred eighty-one".