1981642 has 16 divisors (see below), whose sum is σ = 3225600. Its totient is φ = 907632.

The previous prime is 1981631. The next prime is 1981649. The reversal of 1981642 is 2461891.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1981649) 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, 4983 + ... + 5365.

It is an arithmetic number, because the mean of its divisors is an integer number (201600).

2^1981642 is an apocalyptic number.

1981642 is a deficient number, since it is larger than the sum of its proper divisors (1243958).

1981642 is a wasteful number, since it uses less digits than its factorization.

1981642 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 597.

The product of its digits is 3456, while the sum is 31.

The square root of 1981642 is about 1407.7080663263. The cubic root of 1981642 is about 125.6054256112.

Subtracting 1981642 from its reverse (2461891), we obtain a square (480249 = 693²).

The spelling of 1981642 in words is "one million, nine hundred eighty-one thousand, six hundred forty-two".