9721887 has 8 divisors (see below), whose sum is σ = 14814336. Its totient is φ = 5555352.

The previous prime is 9721883. The next prime is 9721891. The reversal of 9721887 is 7881279.

It is an interprime number because it is at equal distance from previous prime (9721883) and next prime (9721891).

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 9721887 - 2² = 9721883 is a prime.

It is a super-3 number, since 3×9721887³ (a number of 22 digits) contains 333 as substring.

It is a Smith number, since the sum of its digits (42) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9721883) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 231453 + ... + 231494.

It is an arithmetic number, because the mean of its divisors is an integer number (1851792).

Almost surely, 2^9721887 is an apocalyptic number.

9721887 is a deficient number, since it is larger than the sum of its proper divisors (5092449).

9721887 is a wasteful number, since it uses less digits than its factorization.

9721887 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 462957.

The product of its digits is 56448, while the sum is 42.

The square root of 9721887 is about 3117.9940667038. The cubic root of 9721887 is about 213.4274077825.

Subtracting from 9721887 its sum of digits (42), we obtain a triangular number (9721845 = T₄₄₀₉).

The spelling of 9721887 in words is "nine million, seven hundred twenty-one thousand, eight hundred eighty-seven".