19449370521 has 81 divisors (see below), whose sum is σ = 33994442781. Its totient is φ = 10683828288.

The previous prime is 19449370513. The next prime is 19449370529. The reversal of 19449370521 is 12507394491.

The square root of 19449370521 is 139461.

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

19449370521 is a `hidden beast` number, since 1 + 94 + 4 + 9 + 37 + 0 + 521 = 666.

It is an interprime number because it is at equal distance from previous prime (19449370513) and next prime (19449370529).

It can be written as a sum of positive squares in 4 ways, for example, as 5221652121 + 14227718400 = 72261^2 + 119280^2 .

It is not a de Polignac number, because 19449370521 - 2³ = 19449370513 is a prime.

It is a super-2 number, since 2×19449370521² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (19449370529) by changing a digit.

It is a polite number, since it can be written in 80 ways as a sum of consecutive naturals, for example, 84931635 + ... + 84931863.

Almost surely, 2^19449370521 is an apocalyptic number.

19449370521 is the 139461-st square number.

19449370521 is the 69731-st centered octagonal number.

It is an amenable number.

19449370521 is a deficient number, since it is larger than the sum of its proper divisors (14545072260).

19449370521 is an equidigital number, since it uses as much as digits as its factorization.

19449370521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 536 (or 268 counting only the distinct ones).

The product of its (nonzero) digits is 272160, while the sum is 45.

The spelling of 19449370521 in words is "nineteen billion, four hundred forty-nine million, three hundred seventy thousand, five hundred twenty-one".