2151605 has 12 divisors (see below), whose sum is σ = 2744580. Its totient is φ = 1618944.

The previous prime is 2151593. The next prime is 2151607. The reversal of 2151605 is 5061512.

It can be written as a sum of positive squares in 6 ways, for example, as 11236 + 2140369 = 106^2 + 1463^2 .

It is not a de Polignac number, because 2151605 - 2⁸ = 2151349 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2151607) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 701 + ... + 2189.

It is an arithmetic number, because the mean of its divisors is an integer number (228715).

2^2151605 is an apocalyptic number.

It is an amenable number.

2151605 is a deficient number, since it is larger than the sum of its proper divisors (592975).

2151605 is a wasteful number, since it uses less digits than its factorization.

2151605 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1528 (or 1511 counting only the distinct ones).

The product of its (nonzero) digits is 300, while the sum is 20.

The square root of 2151605 is about 1466.8350282155. The cubic root of 2151605 is about 129.0983965739.

The spelling of 2151605 in words is "two million, one hundred fifty-one thousand, six hundred five".