3781621831645 has 32 divisors (see below), whose sum is σ = 5249079779328. Its totient is φ = 2561688756288.

The previous prime is 3781621831633. The next prime is 3781621831703. The reversal of 3781621831645 is 5461381261873.

It is a cyclic number.

It is not a de Polignac number, because 3781621831645 - 2⁷ = 3781621831517 is a prime.

It is a super-3 number, since 3×3781621831645³ (a number of 39 digits) contains 333 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 50704372 + ... + 50778898.

It is an arithmetic number, because the mean of its divisors is an integer number (164033743104).

Almost surely, 2^{3781621831645} is an apocalyptic number.

3781621831645 is a gapful number since it is divisible by the number (35) formed by its first and last digit.

It is an amenable number.

3781621831645 is a deficient number, since it is larger than the sum of its proper divisors (1467457947683).

3781621831645 is a wasteful number, since it uses less digits than its factorization.

3781621831645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 92089.

The product of its digits is 5806080, while the sum is 55.

The spelling of 3781621831645 in words is "three trillion, seven hundred eighty-one billion, six hundred twenty-one million, eight hundred thirty-one thousand, six hundred forty-five".