122785721 has 4 divisors (see below), whose sum is σ = 126104292. Its totient is φ = 119467152.

The previous prime is 122785717. The next prime is 122785723. The reversal of 122785721 is 127587221.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 127587221 = 823 ⋅155027.

It can be written as a sum of positive squares in 2 ways, for example, as 108910096 + 13875625 = 10436^2 + 3725^2 .

It is a cyclic number.

It is not a de Polignac number, because 122785721 - 2² = 122785717 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (122785723) 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, 1659230 + ... + 1659303.

It is an arithmetic number, because the mean of its divisors is an integer number (31526073).

Almost surely, 2^122785721 is an apocalyptic number.

It is an amenable number.

122785721 is a deficient number, since it is larger than the sum of its proper divisors (3318571).

122785721 is an equidigital number, since it uses as much as digits as its factorization.

122785721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3318570.

The product of its digits is 15680, while the sum is 35.

The square root of 122785721 is about 11080.8718519799. The cubic root of 122785721 is about 497.0300213841.

The spelling of 122785721 in words is "one hundred twenty-two million, seven hundred eighty-five thousand, seven hundred twenty-one".