66150581 has 4 divisors (see below), whose sum is σ = 75600672. Its totient is φ = 56700492.

The previous prime is 66150577. The next prime is 66150583. The reversal of 66150581 is 18505166.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 18505166 = 2 ⋅9252583.

It is a cyclic number.

It is not a de Polignac number, because 66150581 - 2² = 66150577 is a prime.

It is a super-2 number, since 2×66150581² = 8751798733275122, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66150583) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4725035 + ... + 4725048.

It is an arithmetic number, because the mean of its divisors is an integer number (18900168).

Almost surely, 2^66150581 is an apocalyptic number.

It is an amenable number.

66150581 is a deficient number, since it is larger than the sum of its proper divisors (9450091).

66150581 is an equidigital number, since it uses as much as digits as its factorization.

66150581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9450090.

The product of its (nonzero) digits is 7200, while the sum is 32.

The square root of 66150581 is about 8133.3007444702. The cubic root of 66150581 is about 404.4311090082.

The spelling of 66150581 in words is "sixty-six million, one hundred fifty thousand, five hundred eighty-one".