8637921 has 42 divisors (see below), whose sum is σ = 14093142. Its totient is φ = 5287680.

The previous prime is 8637869. The next prime is 8637929. The reversal of 8637921 is 1297368.

8637921 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 3 ways, for example, as 1347921 + 7290000 = 1161^2 + 2700^2 .

It is not a de Polignac number, because 8637921 - 2¹⁵ = 8605153 is a prime.

It is a super-2 number, since 2×8637921² = 149227358404482, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (8637929) by changing a digit.

It is a polite number, since it can be written in 41 ways as a sum of consecutive naturals, for example, 210661 + ... + 210701.

It is an arithmetic number, because the mean of its divisors is an integer number (335551).

Almost surely, 2^8637921 is an apocalyptic number.

8637921 is a gapful number since it is divisible by the number (81) formed by its first and last digit.

It is an amenable number.

8637921 is a deficient number, since it is larger than the sum of its proper divisors (5455221).

8637921 is an equidigital number, since it uses as much as digits as its factorization.

8637921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 93 (or 61 counting only the distinct ones).

The product of its digits is 18144, while the sum is 36.

The square root of 8637921 is about 2939.0340249817. The cubic root of 8637921 is about 205.1806537624.

The spelling of 8637921 in words is "eight million, six hundred thirty-seven thousand, nine hundred twenty-one".