1381984021 has 4 divisors (see below), whose sum is σ = 1507618944. Its totient is φ = 1256349100.

The previous prime is 1381984001. The next prime is 1381984039. The reversal of 1381984021 is 1204891831.

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 1381984021 - 2⁵ = 1381983989 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1381984001) 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 3 ways as a sum of consecutive naturals, for example, 62817445 + ... + 62817466.

It is an arithmetic number, because the mean of its divisors is an integer number (376904736).

Almost surely, 2^1381984021 is an apocalyptic number.

1381984021 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1381984021 is a deficient number, since it is larger than the sum of its proper divisors (125634923).

1381984021 is a wasteful number, since it uses less digits than its factorization.

1381984021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 125634922.

The product of its (nonzero) digits is 13824, while the sum is 37.

The square root of 1381984021 is about 37175.0456758294. The cubic root of 1381984021 is about 1113.8695725451.

The spelling of 1381984021 in words is "one billion, three hundred eighty-one million, nine hundred eighty-four thousand, twenty-one".