451981 has 4 divisors (see below), whose sum is σ = 453600. Its totient is φ = 450364.

The previous prime is 451967. The next prime is 451987. The reversal of 451981 is 189154.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-451981 is a prime.

It is a super-2 number, since 2×451981² = 408573648722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (451987) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 271 + ... + 988.

It is an arithmetic number, because the mean of its divisors is an integer number (113400).

2⁴⁵¹⁹⁸¹ is an apocalyptic number.

It is an amenable number.

451981 is a deficient number, since it is larger than the sum of its proper divisors (1619).

451981 is a wasteful number, since it uses less digits than its factorization.

451981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1618.

The product of its digits is 1440, while the sum is 28.

The square root of 451981 is about 672.2953220126. The cubic root of 451981 is about 76.7432274473.

The spelling of 451981 in words is "four hundred fifty-one thousand, nine hundred eighty-one".