681958121 has 8 divisors (see below), whose sum is σ = 734623680. Its totient is φ = 629322192.

The previous prime is 681958103. The next prime is 681958153. The reversal of 681958121 is 121859186.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-681958121 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (681958421) 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, 71966 + ... + 80888.

It is an arithmetic number, because the mean of its divisors is an integer number (91827960).

Almost surely, 2^681958121 is an apocalyptic number.

It is an amenable number.

681958121 is a deficient number, since it is larger than the sum of its proper divisors (52665559).

681958121 is a wasteful number, since it uses less digits than its factorization.

681958121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14815.

The product of its digits is 34560, while the sum is 41.

The square root of 681958121 is about 26114.3278871963. The cubic root of 681958121 is about 880.2091965634.

The spelling of 681958121 in words is "six hundred eighty-one million, nine hundred fifty-eight thousand, one hundred twenty-one".