1881640 has 16 divisors (see below), whose sum is σ = 4233780. Its totient is φ = 752640.

The previous prime is 1881631. The next prime is 1881641. The reversal of 1881640 is 461881.

It can be written as a sum of positive squares in 2 ways, for example, as 1747684 + 133956 = 1322^2 + 366^2 .

It is a junction number, because it is equal to n+sod(n) for n = 1881599 and 1881608.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1881641) 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, 23481 + ... + 23560.

2^1881640 is an apocalyptic number.

1881640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1881640 is an abundant number, since it is smaller than the sum of its proper divisors (2352140).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1881640 is a wasteful number, since it uses less digits than its factorization.

1881640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 47052 (or 47048 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 28.

The square root of 1881640 is about 1371.7288361772. The cubic root of 1881640 is about 123.4559935438.

The spelling of 1881640 in words is "one million, eight hundred eighty-one thousand, six hundred forty".