681351633 has 12 divisors (see below), whose sum is σ = 1010774388. Its totient is φ = 441957600.

The previous prime is 681351631. The next prime is 681351637. The reversal of 681351633 is 336153186.

It is a happy number.

681351633 is a `hidden beast` number, since 6 + 8 + 13 + 5 + 1 + 633 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 524776464 + 156575169 = 22908^2 + 12513^2 .

It is not a de Polignac number, because 681351633 - 2¹ = 681351631 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (681351631) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1022718 + ... + 1023383.

It is an arithmetic number, because the mean of its divisors is an integer number (84231199).

Almost surely, 2^681351633 is an apocalyptic number.

It is an amenable number.

681351633 is a deficient number, since it is larger than the sum of its proper divisors (329422755).

681351633 is a wasteful number, since it uses less digits than its factorization.

681351633 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2046144 (or 2046141 counting only the distinct ones).

The product of its digits is 38880, while the sum is 36.

The square root of 681351633 is about 26102.7131348448. The cubic root of 681351633 is about 879.9481860850.

The spelling of 681351633 in words is "six hundred eighty-one million, three hundred fifty-one thousand, six hundred thirty-three".