2191657 has 16 divisors (see below), whose sum is σ = 2564352. Its totient is φ = 1854720.

The previous prime is 2191633. The next prime is 2191687. The reversal of 2191657 is 7561912.

It is a cyclic number.

It is not a de Polignac number, because 2191657 - 2⁷ = 2191529 is a prime.

It is a super-4 number, since 4×2191657⁴ (a number of 26 digits) contains 4444 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2191627) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10282 + ... + 10492.

It is an arithmetic number, because the mean of its divisors is an integer number (160272).

2^2191657 is an apocalyptic number.

It is an amenable number.

2191657 is a deficient number, since it is larger than the sum of its proper divisors (372695).

2191657 is a wasteful number, since it uses less digits than its factorization.

2191657 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 288.

The product of its digits is 3780, while the sum is 31.

The square root of 2191657 is about 1480.4246012547. The cubic root of 2191657 is about 129.8945298389.

The spelling of 2191657 in words is "two million, one hundred ninety-one thousand, six hundred fifty-seven".