64444557421 has 4 divisors (see below), whose sum is σ = 66523414144. Its totient is φ = 62365700700.

The previous prime is 64444557413. The next prime is 64444557427. The reversal of 64444557421 is 12475544446.

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: 12475544446 = 2 ⋅6237772223.

It is a cyclic number.

It is not a de Polignac number, because 64444557421 - 2³ = 64444557413 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64444557427) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1039428315 + ... + 1039428376.

It is an arithmetic number, because the mean of its divisors is an integer number (16630853536).

Almost surely, 2^64444557421 is an apocalyptic number.

It is an amenable number.

64444557421 is a deficient number, since it is larger than the sum of its proper divisors (2078856723).

64444557421 is a wasteful number, since it uses less digits than its factorization.

64444557421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2078856722.

The product of its digits is 2150400, while the sum is 46.

The spelling of 64444557421 in words is "sixty-four billion, four hundred forty-four million, five hundred fifty-seven thousand, four hundred twenty-one".