660061561 has 8 divisors (see below), whose sum is σ = 674619264. Its totient is φ = 645525360.

The previous prime is 660061553. The next prime is 660061573. The reversal of 660061561 is 165160066.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 660061561 - 2³ = 660061553 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (660061531) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 67371 + ... + 76543.

It is an arithmetic number, because the mean of its divisors is an integer number (84327408).

Almost surely, 2^660061561 is an apocalyptic number.

It is an amenable number.

660061561 is a deficient number, since it is larger than the sum of its proper divisors (14557703).

660061561 is a wasteful number, since it uses less digits than its factorization.

660061561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10751.

The product of its (nonzero) digits is 6480, while the sum is 31.

The square root of 660061561 is about 25691.6632587304. The cubic root of 660061561 is about 870.6858382881.

The spelling of 660061561 in words is "six hundred sixty million, sixty-one thousand, five hundred sixty-one".