661601101 has 16 divisors (see below), whose sum is σ = 787442688. Its totient is φ = 543916800.

The previous prime is 661601089. The next prime is 661601119. The reversal of 661601101 is 101106166.

It is not a de Polignac number, because 661601101 - 2¹⁹ = 661076813 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 (661601131) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11031 + ... + 38011.

It is an arithmetic number, because the mean of its divisors is an integer number (49215168).

Almost surely, 2^661601101 is an apocalyptic number.

It is an amenable number.

661601101 is a deficient number, since it is larger than the sum of its proper divisors (125841587).

661601101 is a wasteful number, since it uses less digits than its factorization.

661601101 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27132.

The product of its (nonzero) digits is 216, while the sum is 22.

The square root of 661601101 is about 25721.6076674846. The cubic root of 661601101 is about 871.3622473460.

Adding to 661601101 its reverse (101106166), we get a palindrome (762707267).

The spelling of 661601101 in words is "six hundred sixty-one million, six hundred one thousand, one hundred one".