39947356753921 has 4 divisors (see below), whose sum is σ = 39954695976112. Its totient is φ = 39940017531732.

The previous prime is 39947356753907. The next prime is 39947356753937. The reversal of 39947356753921 is 12935765374993.

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.

It is a cyclic number.

It is not a de Polignac number, because 39947356753921 - 2¹¹ = 39947356751873 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (39947356753951) 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, 3669602931 + ... + 3669613816.

It is an arithmetic number, because the mean of its divisors is an integer number (9988673994028).

Almost surely, 2^{39947356753921} is an apocalyptic number.

It is an amenable number.

39947356753921 is a deficient number, since it is larger than the sum of its proper divisors (7339222191).

39947356753921 is an equidigital number, since it uses as much as digits as its factorization.

39947356753921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7339222190.

The product of its digits is 1157360400, while the sum is 73.

The spelling of 39947356753921 in words is "thirty-nine trillion, nine hundred forty-seven billion, three hundred fifty-six million, seven hundred fifty-three thousand, nine hundred twenty-one".