1381821645 has 32 divisors (see below), whose sum is σ = 2337379200. Its totient is φ = 695153664.

The previous prime is 1381821619. The next prime is 1381821653. The reversal of 1381821645 is 5461281831.

It is not a de Polignac number, because 1381821645 - 2⁵ = 1381821613 is a prime.

It is a super-3 number, since 3×1381821645³ (a number of 28 digits) contains 333 as substring.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

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 31 ways as a sum of consecutive naturals, for example, 56001 + ... + 76809.

It is an arithmetic number, because the mean of its divisors is an integer number (73043100).

Almost surely, 2^1381821645 is an apocalyptic number.

1381821645 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1381821645 is a deficient number, since it is larger than the sum of its proper divisors (955557555).

1381821645 is a wasteful number, since it uses less digits than its factorization.

1381821645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21069.

The product of its digits is 46080, while the sum is 39.

The square root of 1381821645 is about 37172.8616735381. The cubic root of 1381821645 is about 1113.8259461917.

The spelling of 1381821645 in words is "one billion, three hundred eighty-one million, eight hundred twenty-one thousand, six hundred forty-five".