39856213421 has 4 divisors (see below), whose sum is σ = 39856680732. Its totient is φ = 39855746112.

The previous prime is 39856213391. The next prime is 39856213429. The reversal of 39856213421 is 12431265893.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 22525807396 + 17330406025 = 150086^2 + 131645^2 .

It is a cyclic number.

It is not a de Polignac number, because 39856213421 - 2⁶ = 39856213357 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 (39856213429) 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, 65276 + ... + 289781.

It is an arithmetic number, because the mean of its divisors is an integer number (9964170183).

Almost surely, 2^39856213421 is an apocalyptic number.

It is an amenable number.

39856213421 is a deficient number, since it is larger than the sum of its proper divisors (467311).

39856213421 is a wasteful number, since it uses less digits than its factorization.

39856213421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 467310.

The product of its digits is 311040, while the sum is 44.

The spelling of 39856213421 in words is "thirty-nine billion, eight hundred fifty-six million, two hundred thirteen thousand, four hundred twenty-one".