661555250 has 32 divisors (see below), whose sum is σ = 1281150000. Its totient is φ = 255494400.

The previous prime is 661555241. The next prime is 661555267. The reversal of 661555250 is 52555166.

It can be written as a sum of positive squares in 8 ways, for example, as 18983449 + 642571801 = 4357^2 + 25349^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 661555250.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 38375 + ... + 52874.

Almost surely, 2^661555250 is an apocalyptic number.

661555250 is a deficient number, since it is larger than the sum of its proper divisors (619594750).

661555250 is a wasteful number, since it uses less digits than its factorization.

661555250 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 91295 (or 91285 counting only the distinct ones).

The product of its (nonzero) digits is 45000, while the sum is 35.

The square root of 661555250 is about 25720.7163586087. The cubic root of 661555250 is about 871.3421175158.

The spelling of 661555250 in words is "six hundred sixty-one million, five hundred fifty-five thousand, two hundred fifty".