661550654 has 4 divisors (see below), whose sum is σ = 992325984. Its totient is φ = 330775326.

The previous prime is 661550653. The next prime is 661550671. The reversal of 661550654 is 456055166.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661550651) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 165387662 + ... + 165387665.

It is an arithmetic number, because the mean of its divisors is an integer number (248081496).

Almost surely, 2^661550654 is an apocalyptic number.

661550654 is a deficient number, since it is larger than the sum of its proper divisors (330775330).

661550654 is a wasteful number, since it uses less digits than its factorization.

661550654 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 330775329.

The product of its (nonzero) digits is 108000, while the sum is 38.

The square root of 661550654 is about 25720.6270141301. The cubic root of 661550654 is about 871.3400996961.

The spelling of 661550654 in words is "six hundred sixty-one million, five hundred fifty thousand, six hundred fifty-four".