638846438551 has 2 divisors, whose sum is σ = 638846438552. Its totient is φ = 638846438550.

The previous prime is 638846438533. The next prime is 638846438567. The reversal of 638846438551 is 155834648836.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 638846438551 - 2¹⁵ = 638846405783 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 638846438551.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (638846438591) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319423219275 + 319423219276.

It is an arithmetic number, because the mean of its divisors is an integer number (319423219276).

Almost surely, 2^638846438551 is an apocalyptic number.

638846438551 is a deficient number, since it is larger than the sum of its proper divisors (1).

638846438551 is an equidigital number, since it uses as much as digits as its factorization.

638846438551 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 66355200, while the sum is 61.

The spelling of 638846438551 in words is "six hundred thirty-eight billion, eight hundred forty-six million, four hundred thirty-eight thousand, five hundred fifty-one".