661005650 has 24 divisors (see below), whose sum is σ = 1255633920. Its totient is φ = 258775760.

The previous prime is 661005641. The next prime is 661005659. The reversal of 661005650 is 56500166.

It is an interprime number because it is at equal distance from previous prime (661005641) and next prime (661005659).

It is not an unprimeable number, because it can be changed into a prime (661005659) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 138290 + ... + 142989.

It is an arithmetic number, because the mean of its divisors is an integer number (52318080).

Almost surely, 2^661005650 is an apocalyptic number.

661005650 is a deficient number, since it is larger than the sum of its proper divisors (594628270).

661005650 is a wasteful number, since it uses less digits than its factorization.

661005650 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 281338 (or 281333 counting only the distinct ones).

The product of its (nonzero) digits is 5400, while the sum is 29.

The square root of 661005650 is about 25710.0301438952. The cubic root of 661005650 is about 871.1007558131.

The spelling of 661005650 in words is "six hundred sixty-one million, five thousand, six hundred fifty".