661662606 has 48 divisors (see below), whose sum is σ = 1460761344. Its totient is φ = 199650000.

The previous prime is 661662571. The next prime is 661662619. The reversal of 661662606 is 606266166.

661662606 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 2×661662606² = 875594808357422472, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 180411 + ... + 184041.

It is an arithmetic number, because the mean of its divisors is an integer number (30432528).

Almost surely, 2^661662606 is an apocalyptic number.

661662606 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 661662606, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (730380672).

661662606 is an abundant number, since it is smaller than the sum of its proper divisors (799098738).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

661662606 is a wasteful number, since it uses less digits than its factorization.

661662606 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3909 (or 3898 counting only the distinct ones).

The product of its (nonzero) digits is 93312, while the sum is 39.

The square root of 661662606 is about 25722.8032298193. The cubic root of 661662606 is about 871.3892482454.

The spelling of 661662606 in words is "six hundred sixty-one million, six hundred sixty-two thousand, six hundred six".