9881650721 has 2 divisors, whose sum is σ = 9881650722. Its totient is φ = 9881650720.

The previous prime is 9881650693. The next prime is 9881650789. The reversal of 9881650721 is 1270561889.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 9559950625 + 321700096 = 97775^2 + 17936^2 .

It is a cyclic number.

It is not a de Polignac number, because 9881650721 - 2⁶ = 9881650657 is a prime.

It is not a weakly prime, because it can be changed into another prime (9881650021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4940825360 + 4940825361.

It is an arithmetic number, because the mean of its divisors is an integer number (4940825361).

Almost surely, 2^9881650721 is an apocalyptic number.

It is an amenable number.

9881650721 is a deficient number, since it is larger than the sum of its proper divisors (1).

9881650721 is an equidigital number, since it uses as much as digits as its factorization.

9881650721 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 241920, while the sum is 47.

The square root of 9881650721 is about 99406.4923483371. The cubic root of 9881650721 is about 2145.9017456384.

The spelling of 9881650721 in words is "nine billion, eight hundred eighty-one million, six hundred fifty thousand, seven hundred twenty-one".