18982981 has 4 divisors (see below), whose sum is σ = 19808352. Its totient is φ = 18157612.

The previous prime is 18982979. The next prime is 18982987. The reversal of 18982981 is 18928981.

18982981 = T₄₅₄ + T₄₅₅ + ... + T₅₉₁.

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 18982981 - 2¹ = 18982979 is a prime.

It is a super-2 number, since 2×18982981² = 720707135292722, 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 (18982987) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 412651 + ... + 412696.

It is an arithmetic number, because the mean of its divisors is an integer number (4952088).

Almost surely, 2^18982981 is an apocalyptic number.

It is an amenable number.

18982981 is a deficient number, since it is larger than the sum of its proper divisors (825371).

18982981 is an equidigital number, since it uses as much as digits as its factorization.

18982981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 825370.

The product of its digits is 82944, while the sum is 46.

The square root of 18982981 is about 4356.9462929901. The cubic root of 18982981 is about 266.7604682162.

The spelling of 18982981 in words is "eighteen million, nine hundred eighty-two thousand, nine hundred eighty-one".