661550207 has 4 divisors (see below), whose sum is σ = 662666400. Its totient is φ = 660434016.

The previous prime is 661550191. The next prime is 661550243. The reversal of 661550207 is 702055166.

It is a happy number.

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 661550207 - 2⁴ = 661550191 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 (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, 557207 + ... + 558392.

It is an arithmetic number, because the mean of its divisors is an integer number (165666600).

Almost surely, 2^661550207 is an apocalyptic number.

661550207 is a deficient number, since it is larger than the sum of its proper divisors (1116193).

661550207 is a wasteful number, since it uses less digits than its factorization.

661550207 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1116192.

The product of its (nonzero) digits is 12600, while the sum is 32.

The square root of 661550207 is about 25720.6183246049. The cubic root of 661550207 is about 871.3399034455.

The spelling of 661550207 in words is "six hundred sixty-one million, five hundred fifty thousand, two hundred seven".