3861121638 has 16 divisors (see below), whose sum is σ = 8424265536. Its totient is φ = 1170036840.

The previous prime is 3861121633. The next prime is 3861121687. The reversal of 3861121638 is 8361211683.

It is a junction number, because it is equal to n+sod(n) for n = 3861121596 and 3861121605.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3861121633) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 29250856 + ... + 29250987.

It is an arithmetic number, because the mean of its divisors is an integer number (526516596).

Almost surely, 2^3861121638 is an apocalyptic number.

3861121638 is an abundant number, since it is smaller than the sum of its proper divisors (4563143898).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

3861121638 is a wasteful number, since it uses less digits than its factorization.

3861121638 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 58501859.

The product of its digits is 41472, while the sum is 39.

The square root of 3861121638 is about 62137.9243135784. The cubic root of 3861121638 is about 1568.8129339514.

The spelling of 3861121638 in words is "three billion, eight hundred sixty-one million, one hundred twenty-one thousand, six hundred thirty-eight".