1801681 has 12 divisors (see below), whose sum is σ = 2125872. Its totient is φ = 1522248.

The previous prime is 1801673. The next prime is 1801691. The reversal of 1801681 is 1861081.

It is a happy number.

It is not a de Polignac number, because 1801681 - 2³ = 1801673 is a prime.

It is a super-2 number, since 2×1801681² = 6492108851522, which contains 22 as substring.

It is an Ulam number.

1801681 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (1801601) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3846 + ... + 4288.

It is an arithmetic number, because the mean of its divisors is an integer number (177156).

2^1801681 is an apocalyptic number.

It is an amenable number.

1801681 is a deficient number, since it is larger than the sum of its proper divisors (324191).

1801681 is an equidigital number, since it uses as much as digits as its factorization.

1801681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 540 (or 533 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 25.

The square root of 1801681 is about 1342.2671120161. The cubic root of 1801681 is about 121.6818954687.

The spelling of 1801681 in words is "one million, eight hundred one thousand, six hundred eighty-one".