681690849 has 32 divisors (see below), whose sum is σ = 1103665920. Its totient is φ = 365928192.

The previous prime is 681690839. The next prime is 681690851. The reversal of 681690849 is 948096186.

It is a happy number.

It is not a de Polignac number, because 681690849 - 2⁹ = 681690337 is a prime.

It is a super-2 number, since 2×681690849² = 929404827220681602, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (681690839) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 7407 + ... + 37659.

It is an arithmetic number, because the mean of its divisors is an integer number (34489560).

Almost surely, 2^681690849 is an apocalyptic number.

It is an amenable number.

681690849 is a deficient number, since it is larger than the sum of its proper divisors (421975071).

681690849 is a wasteful number, since it uses less digits than its factorization.

681690849 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30329.

The product of its (nonzero) digits is 746496, while the sum is 51.

The square root of 681690849 is about 26109.2100416692. The cubic root of 681690849 is about 880.0941914502.

The spelling of 681690849 in words is "six hundred eighty-one million, six hundred ninety thousand, eight hundred forty-nine".