661550105 has 4 divisors (see below), whose sum is σ = 793860132. Its totient is φ = 529240080.

The previous prime is 661550069. The next prime is 661550107. The reversal of 661550105 is 501055166.

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

It can be written as a sum of positive squares in 2 ways, for example, as 458088409 + 203461696 = 21403^2 + 14264^2 .

It is not a de Polignac number, because 661550105 - 2²⁸ = 393114649 is a prime.

It is a super-2 number, since 2×661550105² = 875297082851022050, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (661550107) 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, 66155006 + ... + 66155015.

It is an arithmetic number, because the mean of its divisors is an integer number (198465033).

Almost surely, 2^661550105 is an apocalyptic number.

It is an amenable number.

661550105 is a deficient number, since it is larger than the sum of its proper divisors (132310027).

661550105 is a wasteful number, since it uses less digits than its factorization.

661550105 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 132310026.

The product of its (nonzero) digits is 4500, while the sum is 29.

The square root of 661550105 is about 25720.6163417598. The cubic root of 661550105 is about 871.3398586635.

The spelling of 661550105 in words is "six hundred sixty-one million, five hundred fifty thousand, one hundred five".