64206722521 has 4 divisors (see below), whose sum is σ = 64271513344. Its totient is φ = 64141931700.

The previous prime is 64206722509. The next prime is 64206722539. The reversal of 64206722521 is 12522760246.

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, and also an emirpimes, since its reverse is a distinct semiprime: 12522760246 = 2 ⋅6261380123.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-64206722521 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (64206722581) 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, 32393925 + ... + 32395906.

It is an arithmetic number, because the mean of its divisors is an integer number (16067878336).

Almost surely, 2^64206722521 is an apocalyptic number.

It is an amenable number.

64206722521 is a deficient number, since it is larger than the sum of its proper divisors (64790823).

64206722521 is an equidigital number, since it uses as much as digits as its factorization.

64206722521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 64790822.

The product of its (nonzero) digits is 80640, while the sum is 37.

The spelling of 64206722521 in words is "sixty-four billion, two hundred six million, seven hundred twenty-two thousand, five hundred twenty-one".