39873821 has 8 divisors (see below), whose sum is σ = 43067640. Its totient is φ = 36698112.

The previous prime is 39873817. The next prime is 39873833. The reversal of 39873821 is 12837893.

It can be written as a sum of positive squares in 4 ways, for example, as 5522500 + 34351321 = 2350^2 + 5861^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 39873821 - 2² = 39873817 is a prime.

It is a super-2 number, since 2×39873821² = 3179843202280082, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (39870821) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 245 + ... + 8933.

It is an arithmetic number, because the mean of its divisors is an integer number (5383455).

Almost surely, 2^39873821 is an apocalyptic number.

It is an amenable number.

39873821 is a deficient number, since it is larger than the sum of its proper divisors (3193819).

39873821 is a wasteful number, since it uses less digits than its factorization.

39873821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9055.

The product of its digits is 72576, while the sum is 41.

The square root of 39873821 is about 6314.5721153535. The cubic root of 39873821 is about 341.6352054579.

The spelling of 39873821 in words is "thirty-nine million, eight hundred seventy-three thousand, eight hundred twenty-one".