1981311421 has 16 divisors (see below), whose sum is σ = 2025777600. Its totient is φ = 1937520000.

The previous prime is 1981311419. The next prime is 1981311439. The reversal of 1981311421 is 1241131891.

It is a cyclic number.

It is not a de Polignac number, because 1981311421 - 2¹ = 1981311419 is a prime.

It is a super-3 number, since 3×1981311421³ (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 (1981311491) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3802641 + ... + 3803161.

It is an arithmetic number, because the mean of its divisors is an integer number (126611100).

Almost surely, 2^1981311421 is an apocalyptic number.

It is an amenable number.

1981311421 is a deficient number, since it is larger than the sum of its proper divisors (44466179).

1981311421 is a wasteful number, since it uses less digits than its factorization.

1981311421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1020.

The product of its digits is 1728, while the sum is 31.

The square root of 1981311421 is about 44511.9244809748. The cubic root of 1981311421 is about 1255.9844069240.

The spelling of 1981311421 in words is "one billion, nine hundred eighty-one million, three hundred eleven thousand, four hundred twenty-one".