1855381 has 8 divisors (see below), whose sum is σ = 2089728. Its totient is φ = 1632000.

The previous prime is 1855361. The next prime is 1855393. The reversal of 1855381 is 1835581.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a 4-Lehmer number, since φ(1855381) divides (1855381-1)⁴.

It is a cyclic number.

It is not a de Polignac number, because 1855381 - 2⁵ = 1855349 is a prime.

It is a super-2 number, since 2×1855381² = 6884877310322, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (31).

It is an Ulam number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1855361) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2380 + ... + 3061.

It is an arithmetic number, because the mean of its divisors is an integer number (261216).

2^1855381 is an apocalyptic number.

1855381 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1855381 is a deficient number, since it is larger than the sum of its proper divisors (234347).

1855381 is a wasteful number, since it uses less digits than its factorization.

1855381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5483.

The product of its digits is 4800, while the sum is 31.

The square root of 1855381 is about 1362.1237095066. The cubic root of 1855381 is about 122.8790094098.

Subtracting from 1855381 its product of digits (4800), we obtain a palindrome (1850581).

The spelling of 1855381 in words is "one million, eight hundred fifty-five thousand, three hundred eighty-one".