1656025121 has 4 divisors (see below), whose sum is σ = 1687270932. Its totient is φ = 1624779312.

The previous prime is 1656025117. The next prime is 1656025153. The reversal of 1656025121 is 1215206561.

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 1515934225 + 140090896 = 38935^2 + 11836^2 .

It is a cyclic number.

It is not a de Polignac number, because 1656025121 - 2² = 1656025117 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1656025321) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15622826 + ... + 15622931.

It is an arithmetic number, because the mean of its divisors is an integer number (421817733).

Almost surely, 2^1656025121 is an apocalyptic number.

It is an amenable number.

1656025121 is a deficient number, since it is larger than the sum of its proper divisors (31245811).

1656025121 is an equidigital number, since it uses as much as digits as its factorization.

1656025121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31245810.

The product of its (nonzero) digits is 3600, while the sum is 29.

The square root of 1656025121 is about 40694.2885550294. The cubic root of 1656025121 is about 1183.1023223099.

The spelling of 1656025121 in words is "one billion, six hundred fifty-six million, twenty-five thousand, one hundred twenty-one".