64131661 has 4 divisors (see below), whose sum is σ = 69961824. Its totient is φ = 58301500.

The previous prime is 64131629. The next prime is 64131671. The reversal of 64131661 is 16613146.

64131661 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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.

It is a cyclic number.

It is not a de Polignac number, because 64131661 - 2⁵ = 64131629 is a prime.

It is a super-2 number, since 2×64131661² = 8225739885237842, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64131601) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2915065 + ... + 2915086.

It is an arithmetic number, because the mean of its divisors is an integer number (17490456).

Almost surely, 2^64131661 is an apocalyptic number.

It is an amenable number.

64131661 is a deficient number, since it is larger than the sum of its proper divisors (5830163).

64131661 is a wasteful number, since it uses less digits than its factorization.

64131661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5830162.

The product of its digits is 2592, while the sum is 28.

The square root of 64131661 is about 8008.2245847628. The cubic root of 64131661 is about 400.2741058720.

The spelling of 64131661 in words is "sixty-four million, one hundred thirty-one thousand, six hundred sixty-one".