19437657561 has 45 divisors (see below), whose sum is σ = 33792423951. Its totient is φ = 11102213808.

The previous prime is 19437657527. The next prime is 19437657599. The reversal of 19437657561 is 16575673491.

The square root of 19437657561 is 139419.

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

19437657561 is a `hidden beast` number, since 1 + 9 + 4 + 3 + 7 + 6 + 575 + 61 = 666.

It can be written as a sum of positive squares in only one way, i.e., 19297377225 + 140280336 = 138915^2 + 11844^2 .

It is not a de Polignac number, because 19437657561 - 2¹⁷ = 19437526489 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 19437657498 and 19437657507.

It is not an unprimeable number, because it can be changed into a prime (19437653561) 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 44 ways as a sum of consecutive naturals, for example, 8782291 + ... + 8784503.

Almost surely, 2^19437657561 is an apocalyptic number.

19437657561 is the 139419-th square number.

19437657561 is the 69710-th centered octagonal number.

It is an amenable number.

19437657561 is a deficient number, since it is larger than the sum of its proper divisors (14354766390).

19437657561 is an frugal number, since it uses more digits than its factorization.

19437657561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4452 (or 2223 counting only the distinct ones).

The product of its digits is 4762800, while the sum is 54.

The spelling of 19437657561 in words is "nineteen billion, four hundred thirty-seven million, six hundred fifty-seven thousand, five hundred sixty-one".