681291861 has 8 divisors (see below), whose sum is σ = 909452544. Its totient is φ = 453662880.

The previous prime is 681291857. The next prime is 681291869. The reversal of 681291861 is 168192186.

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

It is not a de Polignac number, because 681291861 - 2² = 681291857 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (681291869) 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, 129925 + ... + 135066.

It is an arithmetic number, because the mean of its divisors is an integer number (113681568).

Almost surely, 2^681291861 is an apocalyptic number.

It is an amenable number.

681291861 is a deficient number, since it is larger than the sum of its proper divisors (228160683).

681291861 is a wasteful number, since it uses less digits than its factorization.

681291861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 265851.

The product of its digits is 41472, while the sum is 42.

The square root of 681291861 is about 26101.5681712804. The cubic root of 681291861 is about 879.9224539967.

The spelling of 681291861 in words is "six hundred eighty-one million, two hundred ninety-one thousand, eight hundred sixty-one".