681150661 has 4 divisors (see below), whose sum is σ = 681204832. Its totient is φ = 681096492.

The previous prime is 681150643. The next prime is 681150683. The reversal of 681150661 is 166051186.

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 a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 681150661 - 2²⁷ = 546932933 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (681150761) 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, 2680 + ... + 37006.

It is an arithmetic number, because the mean of its divisors is an integer number (170301208).

Almost surely, 2^681150661 is an apocalyptic number.

It is an amenable number.

681150661 is a deficient number, since it is larger than the sum of its proper divisors (54171).

681150661 is a wasteful number, since it uses less digits than its factorization.

681150661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 54170.

The product of its (nonzero) digits is 8640, while the sum is 34.

The square root of 681150661 is about 26098.8632127915. The cubic root of 681150661 is about 879.8616608467.

The spelling of 681150661 in words is "six hundred eighty-one million, one hundred fifty thousand, six hundred sixty-one".