1981421101 has 8 divisors (see below), whose sum is σ = 2179415808. Its totient is φ = 1801290700.

The previous prime is 1981421081. The next prime is 1981421207. The reversal of 1981421101 is 1011241891.

It is not a de Polignac number, because 1981421101 - 2⁹ = 1981420589 is a prime.

It is a super-3 number, since 3×1981421101³ (a number of 29 digits) contains 333 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1981421101.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1981421501) 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, 743005 + ... + 745666.

It is an arithmetic number, because the mean of its divisors is an integer number (272426976).

Almost surely, 2^1981421101 is an apocalyptic number.

1981421101 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1981421101 is a deficient number, since it is larger than the sum of its proper divisors (197994707).

1981421101 is an equidigital number, since it uses as much as digits as its factorization.

1981421101 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1488704 (or 1488682 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 28.

The square root of 1981421101 is about 44513.1564933335. The cubic root of 1981421101 is about 1256.0075824542.

Adding to 1981421101 its reverse (1011241891), we get a palindrome (2992662992).

The spelling of 1981421101 in words is "one billion, nine hundred eighty-one million, four hundred twenty-one thousand, one hundred one".