39728717557 has 4 divisors (see below), whose sum is σ = 39731356960. Its totient is φ = 39726078156.

The previous prime is 39728717507. The next prime is 39728717599. The reversal of 39728717557 is 75571782793.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 75571782793 = 13 ⋅5813214061.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-39728717557 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 39728717495 and 39728717504.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (39728717507) 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, 1296993 + ... + 1327270.

It is an arithmetic number, because the mean of its divisors is an integer number (9932839240).

Almost surely, 2^39728717557 is an apocalyptic number.

It is an amenable number.

39728717557 is a deficient number, since it is larger than the sum of its proper divisors (2639403).

39728717557 is a wasteful number, since it uses less digits than its factorization.

39728717557 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2639402.

The product of its digits is 25930800, while the sum is 61.

The spelling of 39728717557 in words is "thirty-nine billion, seven hundred twenty-eight million, seven hundred seventeen thousand, five hundred fifty-seven".