681856237 has 4 divisors (see below), whose sum is σ = 683212320. Its totient is φ = 680500156.

The previous prime is 681856193. The next prime is 681856243. The reversal of 681856237 is 732658186.

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.

It is a cyclic number.

It is not a de Polignac number, because 681856237 - 2¹⁵ = 681823469 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 (681856267) 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, 677287 + ... + 678292.

It is an arithmetic number, because the mean of its divisors is an integer number (170803080).

Almost surely, 2^681856237 is an apocalyptic number.

It is an amenable number.

681856237 is a deficient number, since it is larger than the sum of its proper divisors (1356083).

681856237 is a wasteful number, since it uses less digits than its factorization.

681856237 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1356082.

The product of its digits is 483840, while the sum is 46.

The square root of 681856237 is about 26112.3770844402. The cubic root of 681856237 is about 880.1653601960.

The spelling of 681856237 in words is "six hundred eighty-one million, eight hundred fifty-six thousand, two hundred thirty-seven".