3865821899544 has 64 divisors (see below), whose sum is σ = 11714611824000. Its totient is φ = 1171461180960.

The previous prime is 3865821899501. The next prime is 3865821899581. The reversal of 3865821899544 is 4459981285683.

3865821899544 is a `hidden beast` number, since 3 + 8 + 6 + 58 + 21 + 8 + 9 + 9 + 544 = 666.

It is a Harshad number since it is a multiple of its sum of digits (72).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 813512334 + ... + 813517085.

It is an arithmetic number, because the mean of its divisors is an integer number (183040809750).

Almost surely, 2^{3865821899544} is an apocalyptic number.

It is an amenable number.

3865821899544 is an abundant number, since it is smaller than the sum of its proper divisors (7848789924456).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

3865821899544 is a wasteful number, since it uses less digits than its factorization.

3865821899544 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1627029445 (or 1627029435 counting only the distinct ones).

The product of its digits is 597196800, while the sum is 72.

The spelling of 3865821899544 in words is "three trillion, eight hundred sixty-five billion, eight hundred twenty-one million, eight hundred ninety-nine thousand, five hundred forty-four".