661435801 has 8 divisors (see below), whose sum is σ = 718974144. Its totient is φ = 604848720.

The previous prime is 661435793. The next prime is 661435811. The reversal of 661435801 is 108534166.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 661435801 - 2³ = 661435793 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (661435811) 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 7 ways as a sum of consecutive naturals, for example, 236365 + ... + 239146.

It is an arithmetic number, because the mean of its divisors is an integer number (89871768).

Almost surely, 2^661435801 is an apocalyptic number.

It is an amenable number.

661435801 is a deficient number, since it is larger than the sum of its proper divisors (57538343).

661435801 is a wasteful number, since it uses less digits than its factorization.

661435801 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 475631.

The product of its (nonzero) digits is 17280, while the sum is 34.

The square root of 661435801 is about 25718.3942150361. The cubic root of 661435801 is about 871.2896718033.

Adding to 661435801 its reverse (108534166), we get a palindrome (769969967).

The spelling of 661435801 in words is "six hundred sixty-one million, four hundred thirty-five thousand, eight hundred one".