40666 has 4 divisors (see below), whose sum is σ = 61002. Its totient is φ = 20332.

The previous prime is 40639. The next prime is 40693. The reversal of 40666 is 66604.

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

It is an interprime number because it is at equal distance from previous prime (40639) and next prime (40693).

It can be written as a sum of positive squares in only one way, i.e., 24025 + 16641 = 155^2 + 129^2 .

40666 is a modest number, since divided by 666 gives 40 as remainder.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10165 + ... + 10168.

2⁴⁰⁶⁶⁶ is an apocalyptic number.

40666 is a deficient number, since it is larger than the sum of its proper divisors (20336).

40666 is a wasteful number, since it uses less digits than its factorization.

40666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20335.

The product of its (nonzero) digits is 864, while the sum is 22.

The square root of 40666 is about 201.6581265409. The cubic root of 40666 is about 34.3882824703.

It can be divided in two parts, 406 and 66, that multiplied together give a triangular number (26796 = T₂₃₁).

The spelling of 40666 in words is "forty thousand, six hundred sixty-six".