1656121 has 2 divisors, whose sum is σ = 1656122. Its totient is φ = 1656120.

The previous prime is 1656119. The next prime is 1656131. The reversal of 1656121 is 1216561.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 881721 + 774400 = 939^2 + 880^2 .

It is an emirp because it is prime and its reverse (1216561) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1656121 - 2¹ = 1656119 is a prime.

Together with 1656119, it forms a pair of twin primes.

It is an alternating number because its digits alternate between odd and even.

It is equal to p₁₂₅₀₇₇ and since 1656121 and 125077 have the same sum of digits, it is a Honaker prime.

It is a junction number, because it is equal to n+sod(n) for n = 1656092 and 1656101.

It is not a weakly prime, because it can be changed into another prime (1656101) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 828060 + 828061.

It is an arithmetic number, because the mean of its divisors is an integer number (828061).

2^1656121 is an apocalyptic number.

It is an amenable number.

1656121 is a deficient number, since it is larger than the sum of its proper divisors (1).

1656121 is an equidigital number, since it uses as much as digits as its factorization.

1656121 is an evil number, because the sum of its binary digits is even.

The product of its digits is 360, while the sum is 22.

The square root of 1656121 is about 1286.9036482970. The cubic root of 1656121 is about 118.3125154588.

The spelling of 1656121 in words is "one million, six hundred fifty-six thousand, one hundred twenty-one".