681929905 has 16 divisors (see below), whose sum is σ = 838791360. Its totient is φ = 531937728.

The previous prime is 681929873. The next prime is 681929923. The reversal of 681929905 is 509929186.

It is a cyclic number.

It is not a de Polignac number, because 681929905 - 2⁵ = 681929873 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 139279 + ... + 144091.

It is an arithmetic number, because the mean of its divisors is an integer number (52424460).

Almost surely, 2^681929905 is an apocalyptic number.

It is an amenable number.

681929905 is a deficient number, since it is larger than the sum of its proper divisors (156861455).

681929905 is a wasteful number, since it uses less digits than its factorization.

681929905 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5520.

The product of its (nonzero) digits is 349920, while the sum is 49.

The square root of 681929905 is about 26113.7876417803. The cubic root of 681929905 is about 880.1970568515.

The spelling of 681929905 in words is "six hundred eighty-one million, nine hundred twenty-nine thousand, nine hundred five".