84221981 has 8 divisors (see below), whose sum is σ = 85252824. Its totient is φ = 83195200.

The previous prime is 84221959. The next prime is 84221987. The reversal of 84221981 is 18912248.

It can be written as a sum of positive squares in 4 ways, for example, as 28793956 + 55428025 = 5366^2 + 7445^2 .

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-84221981 is a prime.

It is a super-2 number, since 2×84221981² = 14186684167128722, 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 (84221987) 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, 65315 + ... + 66591.

It is an arithmetic number, because the mean of its divisors is an integer number (10656603).

Almost surely, 2^84221981 is an apocalyptic number.

It is an amenable number.

84221981 is a deficient number, since it is larger than the sum of its proper divisors (1030843).

84221981 is a wasteful number, since it uses less digits than its factorization.

84221981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2031.

The product of its digits is 9216, while the sum is 35.

The square root of 84221981 is about 9177.2534562362. The cubic root of 84221981 is about 438.3373564217.

The spelling of 84221981 in words is "eighty-four million, two hundred twenty-one thousand, nine hundred eighty-one".