2131945 has 4 divisors (see below), whose sum is σ = 2558340. Its totient is φ = 1705552.

The previous prime is 2131937. The next prime is 2131951. The reversal of 2131945 is 5491312.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 974169 + 1157776 = 987^2 + 1076^2 .

It is a cyclic number.

It is not a de Polignac number, because 2131945 - 2³ = 2131937 is a prime.

2131945 is a lucky number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 213190 + ... + 213199.

It is an arithmetic number, because the mean of its divisors is an integer number (639585).

2^2131945 is an apocalyptic number.

It is an amenable number.

2131945 is a deficient number, since it is larger than the sum of its proper divisors (426395).

2131945 is an equidigital number, since it uses as much as digits as its factorization.

2131945 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 426394.

The product of its digits is 1080, while the sum is 25.

The square root of 2131945 is about 1460.1181459046. The cubic root of 2131945 is about 128.7039864479.

The spelling of 2131945 in words is "two million, one hundred thirty-one thousand, nine hundred forty-five".