661261101 has 8 divisors (see below), whose sum is σ = 881901600. Its totient is φ = 440730672.

The previous prime is 661261099. The next prime is 661261141. The reversal of 661261101 is 101162166.

661261101 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is not a de Polignac number, because 661261101 - 2¹ = 661261099 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661261141) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12295 + ... + 38388.

It is an arithmetic number, because the mean of its divisors is an integer number (110237700).

Almost surely, 2^661261101 is an apocalyptic number.

It is an amenable number.

661261101 is a deficient number, since it is larger than the sum of its proper divisors (220640499).

661261101 is a wasteful number, since it uses less digits than its factorization.

661261101 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55035.

The product of its (nonzero) digits is 432, while the sum is 24.

The square root of 661261101 is about 25714.9975889557. The cubic root of 661261101 is about 871.2129560139.

The spelling of 661261101 in words is "six hundred sixty-one million, two hundred sixty-one thousand, one hundred one".