8521981 has 8 divisors (see below), whose sum is σ = 9717624. Its totient is φ = 7403520.

The previous prime is 8521963. The next prime is 8521999. The reversal of 8521981 is 1891258.

It is an interprime number because it is at equal distance from previous prime (8521963) and next prime (8521999).

It can be written as a sum of positive squares in 4 ways, for example, as 348100 + 8173881 = 590^2 + 2859^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 8521981 - 2⁵ = 8521949 is a prime.

It is a super-2 number, since 2×8521981² = 145248320328722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (8521781) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 19060 + ... + 19501.

It is an arithmetic number, because the mean of its divisors is an integer number (1214703).

Almost surely, 2^8521981 is an apocalyptic number.

It is an amenable number.

8521981 is a deficient number, since it is larger than the sum of its proper divisors (1195643).

8521981 is a wasteful number, since it uses less digits than its factorization.

8521981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38591.

The product of its digits is 5760, while the sum is 34.

The square root of 8521981 is about 2919.2432238510. The cubic root of 8521981 is about 204.2585230058.

The spelling of 8521981 in words is "eight million, five hundred twenty-one thousand, nine hundred eighty-one".