1981956 has 48 divisors (see below), whose sum is σ = 4967424. Its totient is φ = 613536.

The previous prime is 1981949. The next prime is 1981963. The reversal of 1981956 is 6591891.

It is an interprime number because it is at equal distance from previous prime (1981949) and next prime (1981963).

Its product of digits (19440) is a multiple of the sum of its prime factors (240).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11785 + ... + 11951.

It is an arithmetic number, because the mean of its divisors is an integer number (103488).

2^1981956 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1981956, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2483712).

1981956 is an abundant number, since it is smaller than the sum of its proper divisors (2985468).

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

1981956 is a wasteful number, since it uses less digits than its factorization.

1981956 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 240 (or 238 counting only the distinct ones).

The product of its digits is 19440, while the sum is 39.

The square root of 1981956 is about 1407.8195907147. The cubic root of 1981956 is about 125.6120595071.

The spelling of 1981956 in words is "one million, nine hundred eighty-one thousand, nine hundred fifty-six".