1656091 has 4 divisors (see below), whose sum is σ = 1687392. Its totient is φ = 1624792.

The previous prime is 1656079. The next prime is 1656101. The reversal of 1656091 is 1906561.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1906561 = 1277 ⋅1493.

It is a cyclic number.

It is not a de Polignac number, because 1656091 - 2⁷ = 1655963 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1656491) 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, 15571 + ... + 15676.

It is an arithmetic number, because the mean of its divisors is an integer number (421848).

2^1656091 is an apocalyptic number.

1656091 is a deficient number, since it is larger than the sum of its proper divisors (31301).

1656091 is an equidigital number, since it uses as much as digits as its factorization.

1656091 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31300.

The product of its (nonzero) digits is 1620, while the sum is 28.

The square root of 1656091 is about 1286.8919923599. The cubic root of 1656091 is about 118.3118010591.

The spelling of 1656091 in words is "one million, six hundred fifty-six thousand, ninety-one".