638866419501249 has 27 divisors (see below), whose sum is σ = 958254013451137. Its totient is φ = 425909581440588.

The previous prime is 638866419501241. The next prime is 638866419501311. The reversal of 638866419501249 is 942105914668836.

The square root of 638866419501249 is 25275807.

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

638866419501249 is a `hidden beast` number, since 6 + 3 + 8 + 8 + 6 + 64 + 19 + 501 + 2 + 49 = 666.

It is a tau number, because it is divible by the number of its divisors (27).

It is not a de Polignac number, because 638866419501249 - 2³ = 638866419501241 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (638866419501241) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 2047184344 + ... + 2047496390.

Almost surely, 2^{638866419501249} is an apocalyptic number.

638866419501249 is the 25275807-th square number.

638866419501249 is the 12637904-th centered octagonal number.

It is an amenable number.

638866419501249 is a deficient number, since it is larger than the sum of its proper divisors (319387593949888).

638866419501249 is an frugal number, since it uses more digits than its factorization.

638866419501249 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 624118 (or 312050 counting only the distinct ones).

The product of its (nonzero) digits is 537477120, while the sum is 72.

The spelling of 638866419501249 in words is "six hundred thirty-eight trillion, eight hundred sixty-six billion, four hundred nineteen million, five hundred one thousand, two hundred forty-nine".