123664381 has 4 divisors (see below), whose sum is σ = 127928700. Its totient is φ = 119400064.

The previous prime is 123664361. The next prime is 123664403. The reversal of 123664381 is 183466321.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 106275481 + 17388900 = 10309^2 + 4170^2 .

It is a cyclic number.

It is not a de Polignac number, because 123664381 - 2⁷ = 123664253 is a prime.

It is a super-2 number, since 2×123664381² = 30585758256226322, 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 (123664361) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2132116 + ... + 2132173.

It is an arithmetic number, because the mean of its divisors is an integer number (31982175).

Almost surely, 2^123664381 is an apocalyptic number.

It is an amenable number.

123664381 is a deficient number, since it is larger than the sum of its proper divisors (4264319).

123664381 is an equidigital number, since it uses as much as digits as its factorization.

123664381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4264318.

The product of its digits is 20736, while the sum is 34.

The square root of 123664381 is about 11120.4487769154. The cubic root of 123664381 is about 498.2127940679.

The spelling of 123664381 in words is "one hundred twenty-three million, six hundred sixty-four thousand, three hundred eighty-one".