666620061 has 16 divisors (see below), whose sum is σ = 916526016. Its totient is φ = 430766336.

The previous prime is 666620041. The next prime is 666620077. The reversal of 666620061 is 160026666.

666620061 = T₄₉₈₉ + T₄₉₉₀ + ... + T₅₀₄₁.

It is a cyclic number.

It is not a de Polignac number, because 666620061 - 2⁵ = 666620029 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666620041) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 12060 + ... + 38453.

It is an arithmetic number, because the mean of its divisors is an integer number (57282876).

Almost surely, 2^666620061 is an apocalyptic number.

It is an amenable number.

666620061 is a deficient number, since it is larger than the sum of its proper divisors (249905955).

666620061 is a wasteful number, since it uses less digits than its factorization.

666620061 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50652.

The product of its (nonzero) digits is 15552, while the sum is 33.

The square root of 666620061 is about 25818.9864440880. The cubic root of 666620061 is about 873.5601073619.

The spelling of 666620061 in words is "six hundred sixty-six million, six hundred twenty thousand, sixty-one".