64691641 has 16 divisors (see below), whose sum is σ = 75976704. Its totient is φ = 53936064.

The previous prime is 64691639. The next prime is 64691657. The reversal of 64691641 is 14619646.

It is not a de Polignac number, because 64691641 - 2¹ = 64691639 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 64691641.

It is not an unprimeable number, because it can be changed into a prime (64691621) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 46431 + ... + 47803.

It is an arithmetic number, because the mean of its divisors is an integer number (4748544).

Almost surely, 2^64691641 is an apocalyptic number.

It is an amenable number.

64691641 is a deficient number, since it is larger than the sum of its proper divisors (11285063).

64691641 is a wasteful number, since it uses less digits than its factorization.

64691641 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1560.

The product of its digits is 31104, while the sum is 37.

The square root of 64691641 is about 8043.1114004470. Note that the first 3 decimals coincide. The cubic root of 64691641 is about 401.4357590737.

The spelling of 64691641 in words is "sixty-four million, six hundred ninety-one thousand, six hundred forty-one".