2157705 has 32 divisors (see below), whose sum is σ = 4187520. Its totient is φ = 1045440.

The previous prime is 2157679. The next prime is 2157709. The reversal of 2157705 is 5077512.

It is not a de Polignac number, because 2157705 - 2⁶ = 2157641 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (2157709) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 759 + ... + 2211.

It is an arithmetic number, because the mean of its divisors is an integer number (130860).

2^2157705 is an apocalyptic number.

It is an amenable number.

2157705 is a deficient number, since it is larger than the sum of its proper divisors (2029815).

2157705 is a wasteful number, since it uses less digits than its factorization.

2157705 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1478 (or 1472 counting only the distinct ones).

The product of its (nonzero) digits is 2450, while the sum is 27.

The square root of 2157705 is about 1468.9128633108. The cubic root of 2157705 is about 129.2202834408.

The spelling of 2157705 in words is "two million, one hundred fifty-seven thousand, seven hundred five".