39991669 has 2 divisors, whose sum is σ = 39991670. Its totient is φ = 39991668.

The previous prime is 39991619. The next prime is 39991681. The reversal of 39991669 is 96619993.

39991669 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 34374769 + 5616900 = 5863^2 + 2370^2 .

It is a cyclic number.

It is not a de Polignac number, because 39991669 - 2²¹ = 37894517 is a prime.

It is a super-2 number, since 2×39991669² = 3198667178811122, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (39991619) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 19995834 + 19995835.

It is an arithmetic number, because the mean of its divisors is an integer number (19995835).

Almost surely, 2^39991669 is an apocalyptic number.

It is an amenable number.

39991669 is a deficient number, since it is larger than the sum of its proper divisors (1).

39991669 is an equidigital number, since it uses as much as digits as its factorization.

39991669 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 708588, while the sum is 52.

The square root of 39991669 is about 6323.8966626598. The cubic root of 39991669 is about 341.9714446708.

The spelling of 39991669 in words is "thirty-nine million, nine hundred ninety-one thousand, six hundred sixty-nine".