681128554 has 4 divisors (see below), whose sum is σ = 1021692834. Its totient is φ = 340564276.

The previous prime is 681128551. The next prime is 681128573. The reversal of 681128554 is 455821186.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 455821186 = 2 ⋅227910593.

It can be written as a sum of positive squares in only one way, i.e., 344956329 + 336172225 = 18573^2 + 18335^2 .

It is a super-2 number, since 2×681128554² = 927872214148261832, which contains 22 as substring.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (681128551) 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 as a sum of consecutive naturals, namely, 170282137 + ... + 170282140.

Almost surely, 2^681128554 is an apocalyptic number.

681128554 is a deficient number, since it is larger than the sum of its proper divisors (340564280).

681128554 is a wasteful number, since it uses less digits than its factorization.

681128554 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 340564279.

The product of its digits is 76800, while the sum is 40.

The square root of 681128554 is about 26098.4396851613. The cubic root of 681128554 is about 879.8521419971.

The spelling of 681128554 in words is "six hundred eighty-one million, one hundred twenty-eight thousand, five hundred fifty-four".