39871861 has 4 divisors (see below), whose sum is σ = 41970400. Its totient is φ = 37773324.

The previous prime is 39871849. The next prime is 39871883. The reversal of 39871861 is 16817893.

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, and also an emirpimes, since its reverse is a distinct semiprime: 16817893 = 1459 ⋅11527.

It is a cyclic number.

It is not a de Polignac number, because 39871861 - 2²⁵ = 6317429 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 (39871801) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1049241 + ... + 1049278.

It is an arithmetic number, because the mean of its divisors is an integer number (10492600).

Almost surely, 2^39871861 is an apocalyptic number.

It is an amenable number.

39871861 is a deficient number, since it is larger than the sum of its proper divisors (2098539).

39871861 is a wasteful number, since it uses less digits than its factorization.

39871861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2098538.

The product of its digits is 72576, while the sum is 43.

The square root of 39871861 is about 6314.4169168657. The cubic root of 39871861 is about 341.6296076667.

The spelling of 39871861 in words is "thirty-nine million, eight hundred seventy-one thousand, eight hundred sixty-one".