638823686051 has 4 divisors (see below), whose sum is σ = 638883472512. Its totient is φ = 638763899592.

The previous prime is 638823686047. The next prime is 638823686071. The reversal of 638823686051 is 150686328836.

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 638823686051 - 2² = 638823686047 is a prime.

It is a super-2 number, since 2×638823686051² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (638823686021) 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, 29877200 + ... + 29898573.

It is an arithmetic number, because the mean of its divisors is an integer number (159720868128).

Almost surely, 2^638823686051 is an apocalyptic number.

638823686051 is a deficient number, since it is larger than the sum of its proper divisors (59786461).

638823686051 is a wasteful number, since it uses less digits than its factorization.

638823686051 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 59786460.

The product of its (nonzero) digits is 9953280, while the sum is 56.

The spelling of 638823686051 in words is "six hundred thirty-eight billion, eight hundred twenty-three million, six hundred eighty-six thousand, fifty-one".