423781 has 2 divisors, whose sum is σ = 423782. Its totient is φ = 423780.

The previous prime is 423779. The next prime is 423791. The reversal of 423781 is 187324.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 370881 + 52900 = 609^2 + 230^2 .

It is a cyclic number.

It is not a de Polignac number, because 423781 - 2¹ = 423779 is a prime.

It is a super-2 number, since 2×423781² = 359180671922, which contains 22 as substring.

Together with 423779, it forms a pair of twin primes.

423781 is a lucky number.

It is equal to p₃₅₆₈₃ and since 423781 and 35683 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (423751) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 211890 + 211891.

It is an arithmetic number, because the mean of its divisors is an integer number (211891).

2⁴²³⁷⁸¹ is an apocalyptic number.

It is an amenable number.

423781 is a deficient number, since it is larger than the sum of its proper divisors (1).

423781 is an equidigital number, since it uses as much as digits as its factorization.

423781 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1344, while the sum is 25.

The square root of 423781 is about 650.9846388357. The cubic root of 423781 is about 75.1127784767.

The spelling of 423781 in words is "four hundred twenty-three thousand, seven hundred eighty-one".