9965629621 has 2 divisors, whose sum is σ = 9965629622. Its totient is φ = 9965629620.

The previous prime is 9965629601. The next prime is 9965629627. The reversal of 9965629621 is 1269265699.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 9372950596 + 592679025 = 96814^2 + 24345^2 .

It is a cyclic number.

It is not a de Polignac number, because 9965629621 - 2²⁹ = 9428758709 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (9965629627) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4982814810 + 4982814811.

It is an arithmetic number, because the mean of its divisors is an integer number (4982814811).

Almost surely, 2^9965629621 is an apocalyptic number.

It is an amenable number.

9965629621 is a deficient number, since it is larger than the sum of its proper divisors (1).

9965629621 is an equidigital number, since it uses as much as digits as its factorization.

9965629621 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3149280, while the sum is 55.

The square root of 9965629621 is about 99828.0001853187. Note that the first 3 decimals coincide. The cubic root of 9965629621 is about 2151.9635655220.

The spelling of 9965629621 in words is "nine billion, nine hundred sixty-five million, six hundred twenty-nine thousand, six hundred twenty-one".