39967661 has 4 divisors (see below), whose sum is σ = 40942524. Its totient is φ = 38992800.

The previous prime is 39967639. The next prime is 39967667. The reversal of 39967661 is 16676993.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 16676993 = 829 ⋅20117.

It can be written as a sum of positive squares in 2 ways, for example, as 12823561 + 27144100 = 3581^2 + 5210^2 .

It is a cyclic number.

It is not a de Polignac number, because 39967661 - 2¹⁰ = 39966637 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (39967667) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 487370 + ... + 487451.

It is an arithmetic number, because the mean of its divisors is an integer number (10235631).

Almost surely, 2^39967661 is an apocalyptic number.

It is an amenable number.

39967661 is a deficient number, since it is larger than the sum of its proper divisors (974863).

39967661 is an equidigital number, since it uses as much as digits as its factorization.

39967661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 974862.

The product of its digits is 367416, while the sum is 47.

The square root of 39967661 is about 6321.9981809551. The cubic root of 39967661 is about 341.9029996330.

The spelling of 39967661 in words is "thirty-nine million, nine hundred sixty-seven thousand, six hundred sixty-one".