64590651581 has 8 divisors (see below), whose sum is σ = 68411158200. Its totient is φ = 60772484608.

The previous prime is 64590651529. The next prime is 64590651583. The reversal of 64590651581 is 18515609546.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 8476148356 + 56114503225 = 92066^2 + 236885^2 .

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 64590651581 - 2¹⁰ = 64590650557 is a prime.

It is a super-2 number, since 2×64590651581² (a number of 22 digits) 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 (64590651583) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 527906 + ... + 638643.

It is an arithmetic number, because the mean of its divisors is an integer number (8551394775).

Almost surely, 2^64590651581 is an apocalyptic number.

It is an amenable number.

64590651581 is a deficient number, since it is larger than the sum of its proper divisors (3820506619).

64590651581 is a wasteful number, since it uses less digits than its factorization.

64590651581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1169823.

The product of its (nonzero) digits is 1296000, while the sum is 50.

It can be divided in two parts, 6459065 and 1581, that added together give a palindrome (6460646).

The spelling of 64590651581 in words is "sixty-four billion, five hundred ninety million, six hundred fifty-one thousand, five hundred eighty-one".