721477341781681 has 8 divisors (see below), whose sum is σ = 725310903118464. Its totient is φ = 717644763298560.

The previous prime is 721477341781667. The next prime is 721477341781687. The reversal of 721477341781681 is 186187143774127.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-721477341781681 is a prime.

It is a super-2 number, since 2×721477341781681² (a number of 31 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (721477341781687) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 244241365 + ... + 247177666.

It is an arithmetic number, because the mean of its divisors is an integer number (90663862889808).

Almost surely, 2^{721477341781681} is an apocalyptic number.

It is an amenable number.

721477341781681 is a deficient number, since it is larger than the sum of its proper divisors (3833561336783).

721477341781681 is a wasteful number, since it uses less digits than its factorization.

721477341781681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 491426831.

The product of its digits is 88510464, while the sum is 67.

The spelling of 721477341781681 in words is "seven hundred twenty-one trillion, four hundred seventy-seven billion, three hundred forty-one million, seven hundred eighty-one thousand, six hundred eighty-one".