638890668719 has 4 divisors (see below), whose sum is σ = 639095378880. Its totient is φ = 638685958560.

The previous prime is 638890668649. The next prime is 638890668743. The reversal of 638890668719 is 917866098836.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 638890668719 - 2³⁶ = 570171191983 is a prime.

It is a super-2 number, since 2×638890668719² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638890667719) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 102350399 + ... + 102356640.

It is an arithmetic number, because the mean of its divisors is an integer number (159773844720).

Almost surely, 2^638890668719 is an apocalyptic number.

638890668719 is a deficient number, since it is larger than the sum of its proper divisors (204710161).

638890668719 is a wasteful number, since it uses less digits than its factorization.

638890668719 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 204710160.

The product of its (nonzero) digits is 188116992, while the sum is 71.

The spelling of 638890668719 in words is "six hundred thirty-eight billion, eight hundred ninety million, six hundred sixty-eight thousand, seven hundred nineteen".