39608947681 has 4 divisors (see below), whose sum is σ = 39656727700. Its totient is φ = 39561167664.

The previous prime is 39608947643. The next prime is 39608947709. The reversal of 39608947681 is 18674980693.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 18674980693 = 73547 ⋅253919.

It can be written as a sum of positive squares in 2 ways, for example, as 14829150625 + 24779797056 = 121775^2 + 157416^2 .

It is a cyclic number.

It is not a de Polignac number, because 39608947681 - 2²⁷ = 39474729953 is a prime.

It is a super-2 number, since 2×39608947681² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (39608947621) 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, 23888766 + ... + 23890423.

It is an arithmetic number, because the mean of its divisors is an integer number (9914181925).

Almost surely, 2^39608947681 is an apocalyptic number.

It is an amenable number.

39608947681 is a deficient number, since it is larger than the sum of its proper divisors (47780019).

39608947681 is an equidigital number, since it uses as much as digits as its factorization.

39608947681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 47780018.

The product of its (nonzero) digits is 15676416, while the sum is 61.

The spelling of 39608947681 in words is "thirty-nine billion, six hundred eight million, nine hundred forty-seven thousand, six hundred eighty-one".