9939509621 has 2 divisors, whose sum is σ = 9939509622. Its totient is φ = 9939509620.

The previous prime is 9939509609. The next prime is 9939509627. The reversal of 9939509621 is 1269059399.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 9937896721 + 1612900 = 99689^2 + 1270^2 .

It is an emirp because it is prime and its reverse (1269059399) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 9939509621 - 2¹⁰ = 9939508597 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (9939509627) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4969754810 + 4969754811.

It is an arithmetic number, because the mean of its divisors is an integer number (4969754811).

Almost surely, 2^9939509621 is an apocalyptic number.

It is an amenable number.

9939509621 is a deficient number, since it is larger than the sum of its proper divisors (1).

9939509621 is an equidigital number, since it uses as much as digits as its factorization.

9939509621 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1180980, while the sum is 53.

The square root of 9939509621 is about 99697.0893306319. The cubic root of 9939509621 is about 2150.0818155994.

The spelling of 9939509621 in words is "nine billion, nine hundred thirty-nine million, five hundred nine thousand, six hundred twenty-one".