3865721919 has 16 divisors (see below), whose sum is σ = 5458780512. Its totient is φ = 2424977408.

The previous prime is 3865721879. The next prime is 3865721921. The reversal of 3865721919 is 9191275683.

It is a cyclic number.

It is not a de Polignac number, because 3865721919 - 2¹⁷ = 3865590847 is a prime.

It is a super-2 number, since 2×3865721919² = 29887611910074085122, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (51).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3865621919) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 342937 + ... + 354029.

It is an arithmetic number, because the mean of its divisors is an integer number (341173782).

Almost surely, 2^3865721919 is an apocalyptic number.

3865721919 is a deficient number, since it is larger than the sum of its proper divisors (1593058593).

3865721919 is a wasteful number, since it uses less digits than its factorization.

3865721919 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17946.

The product of its digits is 816480, while the sum is 51.

The square root of 3865721919 is about 62174.9299878979. The cubic root of 3865721919 is about 1569.4357336379.

The spelling of 3865721919 in words is "three billion, eight hundred sixty-five million, seven hundred twenty-one thousand, nine hundred nineteen".