681205651 has 32 divisors (see below), whose sum is σ = 865751040. Its totient is φ = 522539424.

The previous prime is 681205619. The next prime is 681205663. The reversal of 681205651 is 156502186.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 681205651 - 2⁵ = 681205619 is a prime.

It is a super-2 number, since 2×681205651² = 928082277908667602, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (681205601) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 252556 + ... + 255238.

It is an arithmetic number, because the mean of its divisors is an integer number (27054720).

Almost surely, 2^681205651 is an apocalyptic number.

681205651 is a deficient number, since it is larger than the sum of its proper divisors (184545389).

681205651 is a wasteful number, since it uses less digits than its factorization.

681205651 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2815.

The product of its (nonzero) digits is 14400, while the sum is 34.

The square root of 681205651 is about 26099.9166856908. The cubic root of 681205651 is about 879.8853375913.

The spelling of 681205651 in words is "six hundred eighty-one million, two hundred five thousand, six hundred fifty-one".