64020639509 has 4 divisors (see below), whose sum is σ = 64022366304. Its totient is φ = 64018912716.

The previous prime is 64020639493. The next prime is 64020639539. The reversal of 64020639509 is 90593602046.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 64020639509 - 2⁴ = 64020639493 is a prime.

It is a super-2 number, since 2×64020639509² (a number of 22 digits) contains 22 as substring.

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 64020639509.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64020639539) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 806537 + ... + 882350.

It is an arithmetic number, because the mean of its divisors is an integer number (16005591576).

Almost surely, 2^64020639509 is an apocalyptic number.

It is an amenable number.

64020639509 is a deficient number, since it is larger than the sum of its proper divisors (1726795).

64020639509 is a wasteful number, since it uses less digits than its factorization.

64020639509 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1726794.

The product of its (nonzero) digits is 349920, while the sum is 44.

The spelling of 64020639509 in words is "sixty-four billion, twenty million, six hundred thirty-nine thousand, five hundred nine".