4421721781617 has 24 divisors (see below), whose sum is σ = 6858320398272. Its totient is φ = 2526646701600.

The previous prime is 4421721781597. The next prime is 4421721781649. The reversal of 4421721781617 is 7161871271244.

It is a happy number.

It is not a de Polignac number, because 4421721781617 - 2¹¹ = 4421721779569 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 4421721781617.

It is not an unprimeable number, because it can be changed into a prime (4421721781417) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 7633767 + ... + 8192547.

It is an arithmetic number, because the mean of its divisors is an integer number (285763349928).

Almost surely, 2^{4421721781617} is an apocalyptic number.

It is an amenable number.

4421721781617 is a deficient number, since it is larger than the sum of its proper divisors (2436598616655).

4421721781617 is a wasteful number, since it uses less digits than its factorization.

4421721781617 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 612629 (or 612622 counting only the distinct ones).

The product of its digits is 1053696, while the sum is 51.

The spelling of 4421721781617 in words is "four trillion, four hundred twenty-one billion, seven hundred twenty-one million, seven hundred eighty-one thousand, six hundred seventeen".