1981291776 has 36 divisors (see below), whose sum is σ = 5273127552. Its totient is φ = 660430336.

The previous prime is 1981291771. The next prime is 1981291777. The reversal of 1981291776 is 6771921891.

It is a happy number.

It is a super-3 number, since 3×1981291776³ (a number of 29 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1981291771) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1289136 + ... + 1290671.

Almost surely, 2^1981291776 is an apocalyptic number.

1981291776 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

1981291776 is an abundant number, since it is smaller than the sum of its proper divisors (3291835776).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1981291776 is an equidigital number, since it uses as much as digits as its factorization.

1981291776 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2579826 (or 2579812 counting only the distinct ones).

The product of its digits is 381024, while the sum is 51.

The square root of 1981291776 is about 44511.7038092230. The cubic root of 1981291776 is about 1255.9802558190.

The spelling of 1981291776 in words is "one billion, nine hundred eighty-one million, two hundred ninety-one thousand, seven hundred seventy-six".