661522666 has 16 divisors (see below), whose sum is σ = 1200747456. Its totient is φ = 266832576.

The previous prime is 661522657. The next prime is 661522681. The reversal of 661522666 is 666225166.

661522666 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×661522666² = 875224475263495112, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1389516 + ... + 1389991.

It is an arithmetic number, because the mean of its divisors is an integer number (75046716).

Almost surely, 2^661522666 is an apocalyptic number.

661522666 is a deficient number, since it is larger than the sum of its proper divisors (539224790).

661522666 is a wasteful number, since it uses less digits than its factorization.

661522666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2779533.

The product of its digits is 155520, while the sum is 40.

The square root of 661522666 is about 25720.0829314371. The cubic root of 661522666 is about 871.3278116924.

The spelling of 661522666 in words is "six hundred sixty-one million, five hundred twenty-two thousand, six hundred sixty-six".