64999561 has 8 divisors (see below), whose sum is σ = 71025984. Its totient is φ = 58992720.

The previous prime is 64999547. The next prime is 64999579. The reversal of 64999561 is 16599946.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 64999561 - 2⁷ = 64999433 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (64909561) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2551 + ... + 11683.

It is an arithmetic number, because the mean of its divisors is an integer number (8878248).

Almost surely, 2^64999561 is an apocalyptic number.

It is an amenable number.

64999561 is a deficient number, since it is larger than the sum of its proper divisors (6026423).

64999561 is a wasteful number, since it uses less digits than its factorization.

64999561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9791.

The product of its digits is 524880, while the sum is 49.

The square root of 64999561 is about 8062.2305226283. The cubic root of 64999561 is about 402.0716706781.

It can be divided in two parts, 649995 and 61, that added together give a palindrome (650056).

The spelling of 64999561 in words is "sixty-four million, nine hundred ninety-nine thousand, five hundred sixty-one".