66557577 has 8 divisors (see below), whose sum is σ = 88868416. Its totient is φ = 44309232.

The previous prime is 66557549. The next prime is 66557597. The reversal of 66557577 is 77575566.

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

It is not a de Polignac number, because 66557577 - 2⁸ = 66557321 is a prime.

It is a super-2 number, since 2×66557577² = 8859822112221858, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66557597) 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, 13078 + ... + 17439.

It is an arithmetic number, because the mean of its divisors is an integer number (11108552).

Almost surely, 2^66557577 is an apocalyptic number.

It is an amenable number.

66557577 is a deficient number, since it is larger than the sum of its proper divisors (22310839).

66557577 is a wasteful number, since it uses less digits than its factorization.

66557577 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31247.

The product of its digits is 1543500, while the sum is 48.

The square root of 66557577 is about 8158.2827237109. The cubic root of 66557577 is about 405.2588438297.

The spelling of 66557577 in words is "sixty-six million, five hundred fifty-seven thousand, five hundred seventy-seven".