1981281 has 8 divisors (see below), whose sum is σ = 2652544. Its totient is φ = 1315440.

The previous prime is 1981277. The next prime is 1981297. The reversal of 1981281 is 1821891.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1981281 - 2² = 1981277 is a prime.

It is a super-3 number, since 3×1981281³ = 23332403539831233123, which contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1981201) 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, 406 + ... + 2031.

It is an arithmetic number, because the mean of its divisors is an integer number (331568).

2^1981281 is an apocalyptic number.

1981281 is the 813-rd octagonal number.

It is an amenable number.

1981281 is a deficient number, since it is larger than the sum of its proper divisors (671263).

1981281 is a wasteful number, since it uses less digits than its factorization.

1981281 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2711.

The product of its digits is 1152, while the sum is 30.

The square root of 1981281 is about 1407.5798378778. The cubic root of 1981281 is about 125.5977978775.

The spelling of 1981281 in words is "one million, nine hundred eighty-one thousand, two hundred eighty-one".