123281781 has 8 divisors (see below), whose sum is σ = 187857984. Its totient is φ = 70446720.

The previous prime is 123281777. The next prime is 123281789. The reversal of 123281781 is 187182321.

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

It is not a de Polignac number, because 123281781 - 2² = 123281777 is a prime.

It is a super-2 number, since 2×123281781² = 30396795053063922, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (123281789) 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, 2935260 + ... + 2935301.

It is an arithmetic number, because the mean of its divisors is an integer number (23482248).

Almost surely, 2^123281781 is an apocalyptic number.

It is an amenable number.

123281781 is a deficient number, since it is larger than the sum of its proper divisors (64576203).

123281781 is an equidigital number, since it uses as much as digits as its factorization.

123281781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5870571.

The product of its digits is 5376, while the sum is 33.

The square root of 123281781 is about 11103.2329075815. The cubic root of 123281781 is about 497.6984634475.

The spelling of 123281781 in words is "one hundred twenty-three million, two hundred eighty-one thousand, seven hundred eighty-one".