16720817481 has 9 divisors (see below), whose sum is σ = 24152852269. Its totient is φ = 11146953036.

The previous prime is 16720817471. The next prime is 16720817501. The reversal of 16720817481 is 18471802761.

The square root of 16720817481 is 129309.

It is a perfect power (a square), and thus also a powerful number.

16720817481 is a `hidden beast` number, since 167 + 2 + 0 + 8 + 1 + 7 + 481 = 666.

It is a tau number, because it is divible by the number of its divisors (9).

It is a de Polignac number, because none of the positive numbers 2^k-16720817481 is a prime.

It is a super-2 number, since 2×16720817481² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16720817401) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 366376 + ... + 409478.

Almost surely, 2^16720817481 is an apocalyptic number.

16720817481 is the 129309-th square number.

16720817481 is the 64655-th centered octagonal number.

It is an amenable number.

16720817481 is a deficient number, since it is larger than the sum of its proper divisors (7432034788).

16720817481 is an frugal number, since it uses more digits than its factorization.

16720817481 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 86212 (or 43106 counting only the distinct ones).

The product of its (nonzero) digits is 150528, while the sum is 45.

The spelling of 16720817481 in words is "sixteen billion, seven hundred twenty million, eight hundred seventeen thousand, four hundred eighty-one".