1981775 has 12 divisors (see below), whose sum is σ = 2602512. Its totient is φ = 1491840.

The previous prime is 1981753. The next prime is 1981787. The reversal of 1981775 is 5771891.

It is not a de Polignac number, because 1981775 - 2⁶ = 1981711 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1907 + ... + 2756.

It is an arithmetic number, because the mean of its divisors is an integer number (216876).

2^1981775 is an apocalyptic number.

1981775 is a deficient number, since it is larger than the sum of its proper divisors (620737).

1981775 is a wasteful number, since it uses less digits than its factorization.

1981775 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4690 (or 4685 counting only the distinct ones).

The product of its digits is 17640, while the sum is 38.

The square root of 1981775 is about 1407.7553054420. The cubic root of 1981775 is about 125.6082355953.

The spelling of 1981775 in words is "one million, nine hundred eighty-one thousand, seven hundred seventy-five".