681549877901 has 4 divisors (see below), whose sum is σ = 711182481312. Its totient is φ = 651917274492.

The previous prime is 681549877891. The next prime is 681549877963. The reversal of 681549877901 is 109778945186.

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 681549877901 - 2¹⁸ = 681549615757 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 (681549807901) 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, 14816301671 + ... + 14816301716.

It is an arithmetic number, because the mean of its divisors is an integer number (177795620328).

Almost surely, 2^681549877901 is an apocalyptic number.

It is an amenable number.

681549877901 is a deficient number, since it is larger than the sum of its proper divisors (29632603411).

681549877901 is a wasteful number, since it uses less digits than its factorization.

681549877901 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29632603410.

The product of its (nonzero) digits is 30481920, while the sum is 65.

The spelling of 681549877901 in words is "six hundred eighty-one billion, five hundred forty-nine million, eight hundred seventy-seven thousand, nine hundred one".