2661578 has 4 divisors (see below), whose sum is σ = 3992370. Its totient is φ = 1330788.

The previous prime is 2661569. The next prime is 2661611. The reversal of 2661578 is 8751662.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 8751662 = 2 ⋅4375831.

It can be written as a sum of positive squares in only one way, i.e., 2362369 + 299209 = 1537^2 + 547^2 .

It is a nialpdrome in base 12.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 665393 + ... + 665396.

2^2661578 is an apocalyptic number.

2661578 is a deficient number, since it is larger than the sum of its proper divisors (1330792).

2661578 is a wasteful number, since it uses less digits than its factorization.

2661578 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1330791.

The product of its digits is 20160, while the sum is 35.

The square root of 2661578 is about 1631.4343382435. The cubic root of 2661578 is about 138.5839915934.

The spelling of 2661578 in words is "two million, six hundred sixty-one thousand, five hundred seventy-eight".