1981228511 has 8 divisors (see below), whose sum is σ = 1990665600. Its totient is φ = 1971814680.

The previous prime is 1981228499. The next prime is 1981228523. The reversal of 1981228511 is 1158221891.

It is an interprime number because it is at equal distance from previous prime (1981228499) and next prime (1981228523).

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 1981228511 - 2³⁰ = 907486687 is a prime.

It is a super-3 number, since 3×1981228511³ (a number of 29 digits) contains 333 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 (1981225511) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 178556 + ... + 189326.

It is an arithmetic number, because the mean of its divisors is an integer number (248833200).

Almost surely, 2^1981228511 is an apocalyptic number.

1981228511 is a deficient number, since it is larger than the sum of its proper divisors (9437089).

1981228511 is a wasteful number, since it uses less digits than its factorization.

1981228511 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11629.

The product of its digits is 11520, while the sum is 38.

The square root of 1981228511 is about 44510.9931477607. The cubic root of 1981228511 is about 1255.9668873629.

The spelling of 1981228511 in words is "one billion, nine hundred eighty-one million, two hundred twenty-eight thousand, five hundred eleven".