64991841 has 16 divisors (see below), whose sum is σ = 90121728. Its totient is φ = 41616000.

The previous prime is 64991831. The next prime is 64991873. The reversal of 64991841 is 14819946.

It is not a de Polignac number, because 64991841 - 2¹⁰ = 64990817 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 64991793 and 64991802.

It is not an unprimeable number, because it can be changed into a prime (64991831) 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, 10191 + ... + 15291.

It is an arithmetic number, because the mean of its divisors is an integer number (5632608).

Almost surely, 2^64991841 is an apocalyptic number.

It is an amenable number.

64991841 is a deficient number, since it is larger than the sum of its proper divisors (25129887).

64991841 is a wasteful number, since it uses less digits than its factorization.

64991841 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5272.

The product of its digits is 62208, while the sum is 42.

The square root of 64991841 is about 8061.7517327191. The cubic root of 64991841 is about 402.0557520260.

The spelling of 64991841 in words is "sixty-four million, nine hundred ninety-one thousand, eight hundred forty-one".