9869820521 has 4 divisors (see below), whose sum is σ = 10767076944. Its totient is φ = 8972564100.

The previous prime is 9869820511. The next prime is 9869820539. The reversal of 9869820521 is 1250289689.

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 9869820521 - 2²⁶ = 9802711657 is a prime.

It is a super-2 number, since 2×9869820521² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 9869820521.

It is not an unprimeable number, because it can be changed into a prime (9869820511) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 448628195 + ... + 448628216.

It is an arithmetic number, because the mean of its divisors is an integer number (2691769236).

Almost surely, 2^9869820521 is an apocalyptic number.

It is an amenable number.

9869820521 is a deficient number, since it is larger than the sum of its proper divisors (897256423).

9869820521 is a wasteful number, since it uses less digits than its factorization.

9869820521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 897256422.

The product of its (nonzero) digits is 622080, while the sum is 50.

The square root of 9869820521 is about 99346.9703664888. The cubic root of 9869820521 is about 2145.0450539418.

The spelling of 9869820521 in words is "nine billion, eight hundred sixty-nine million, eight hundred twenty thousand, five hundred twenty-one".