681506129 has 4 divisors (see below), whose sum is σ = 681594480. Its totient is φ = 681417780.

The previous prime is 681506113. The next prime is 681506131. The reversal of 681506129 is 921605186.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 921605186 = 2 ⋅460802593.

It is a cyclic number.

It is not a de Polignac number, because 681506129 - 2⁴ = 681506113 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 681506092 and 681506101.

It is not an unprimeable number, because it can be changed into a prime (681506159) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 31367 + ... + 48444.

It is an arithmetic number, because the mean of its divisors is an integer number (170398620).

Almost surely, 2^681506129 is an apocalyptic number.

It is an amenable number.

681506129 is a deficient number, since it is larger than the sum of its proper divisors (88351).

681506129 is an equidigital number, since it uses as much as digits as its factorization.

681506129 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 88350.

The product of its (nonzero) digits is 25920, while the sum is 38.

The square root of 681506129 is about 26105.6723529581. The cubic root of 681506129 is about 880.0146902679.

The spelling of 681506129 in words is "six hundred eighty-one million, five hundred six thousand, one hundred twenty-nine".