64181661 has 16 divisors (see below), whose sum is σ = 89579520. Its totient is φ = 40797680.

The previous prime is 64181651. The next prime is 64181683. The reversal of 64181661 is 16618146.

It is a cyclic number.

It is not a de Polignac number, because 64181661 - 2⁵ = 64181629 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64181641) 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, 23476 + ... + 26066.

It is an arithmetic number, because the mean of its divisors is an integer number (5598720).

Almost surely, 2^64181661 is an apocalyptic number.

It is an amenable number.

64181661 is a deficient number, since it is larger than the sum of its proper divisors (25397859).

64181661 is a wasteful number, since it uses less digits than its factorization.

64181661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2976.

The product of its digits is 6912, while the sum is 33.

The square root of 64181661 is about 8011.3457670981. The cubic root of 64181661 is about 400.3781028995.

The spelling of 64181661 in words is "sixty-four million, one hundred eighty-one thousand, six hundred sixty-one".