123245781 has 4 divisors (see below), whose sum is σ = 164327712. Its totient is φ = 82163852.

The previous prime is 123245693. The next prime is 123245789. The reversal of 123245781 is 187542321.

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, and also an emirpimes, since its reverse is a distinct semiprime: 187542321 = 3 ⋅62514107.

It is a cyclic number.

It is not a de Polignac number, because 123245781 - 2⁷ = 123245653 is a prime.

It is a super-2 number, since 2×123245781² = 30379045068599922, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (123245789) 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, 20540961 + ... + 20540966.

It is an arithmetic number, because the mean of its divisors is an integer number (41081928).

Almost surely, 2^123245781 is an apocalyptic number.

It is an amenable number.

123245781 is a deficient number, since it is larger than the sum of its proper divisors (41081931).

123245781 is an equidigital number, since it uses as much as digits as its factorization.

123245781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41081930.

The product of its digits is 13440, while the sum is 33.

The square root of 123245781 is about 11101.6116397575. The cubic root of 123245781 is about 497.6500137663.

The spelling of 123245781 in words is "one hundred twenty-three million, two hundred forty-five thousand, seven hundred eighty-one".