2509666 has 4 divisors (see below), whose sum is σ = 3764502. Its totient is φ = 1254832.

The previous prime is 2509649. The next prime is 2509679. The reversal of 2509666 is 6669052.

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

It can be written as a sum of positive squares in only one way, i.e., 2325625 + 184041 = 1525^2 + 429^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 627415 + ... + 627418.

2^2509666 is an apocalyptic number.

2509666 is a deficient number, since it is larger than the sum of its proper divisors (1254836).

2509666 is a wasteful number, since it uses less digits than its factorization.

2509666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1254835.

The product of its (nonzero) digits is 19440, while the sum is 34.

The square root of 2509666 is about 1584.1925388033. The cubic root of 2509666 is about 135.8955729508.

The spelling of 2509666 in words is "two million, five hundred nine thousand, six hundred sixty-six".