661298739 has 4 divisors (see below), whose sum is σ = 881731656. Its totient is φ = 440865824.

The previous prime is 661298731. The next prime is 661298753. The reversal of 661298739 is 937892166.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 661298739 - 2³ = 661298731 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 661298691 and 661298700.

It is not an unprimeable number, because it can be changed into a prime (661298731) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 110216454 + ... + 110216459.

It is an arithmetic number, because the mean of its divisors is an integer number (220432914).

Almost surely, 2^661298739 is an apocalyptic number.

661298739 is a deficient number, since it is larger than the sum of its proper divisors (220432917).

661298739 is a wasteful number, since it uses less digits than its factorization.

661298739 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 220432916.

The product of its digits is 979776, while the sum is 51.

The square root of 661298739 is about 25715.7294082824. The cubic root of 661298739 is about 871.2294850829.

The spelling of 661298739 in words is "six hundred sixty-one million, two hundred ninety-eight thousand, seven hundred thirty-nine".