9850661721 has 16 divisors (see below), whose sum is σ = 14704979520. Its totient is φ = 6516974880.

The previous prime is 9850661699. The next prime is 9850661729. The reversal of 9850661721 is 1271660589.

9850661721 is a `hidden beast` number, since 9 + 8 + 5 + 0 + 6 + 617 + 21 = 666.

It is not a de Polignac number, because 9850661721 - 2⁷ = 9850661593 is a prime.

It is not an unprimeable number, because it can be changed into a prime (9850661729) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1388980 + ... + 1396053.

It is an arithmetic number, because the mean of its divisors is an integer number (919061220).

Almost surely, 2^9850661721 is an apocalyptic number.

It is an amenable number.

9850661721 is a deficient number, since it is larger than the sum of its proper divisors (4854317799).

9850661721 is a wasteful number, since it uses less digits than its factorization.

9850661721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2785173 (or 2785167 counting only the distinct ones).

The product of its (nonzero) digits is 181440, while the sum is 45.

The square root of 9850661721 is about 99250.4998526456. The cubic root of 9850661721 is about 2143.6562036486.

The spelling of 9850661721 in words is "nine billion, eight hundred fifty million, six hundred sixty-one thousand, seven hundred twenty-one".