2121307638 has 16 divisors (see below), whose sum is σ = 4258390320. Its totient is φ = 704473376.

The previous prime is 2121307621. The next prime is 2121307663. The reversal of 2121307638 is 8367031212.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 2121307599 and 2121307608.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 655545 + ... + 658772.

It is an arithmetic number, because the mean of its divisors is an integer number (266149395).

Almost surely, 2^2121307638 is an apocalyptic number.

2121307638 is an abundant number, since it is smaller than the sum of its proper divisors (2137082682).

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

2121307638 is a wasteful number, since it uses less digits than its factorization.

2121307638 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1314591.

The product of its (nonzero) digits is 12096, while the sum is 33.

The square root of 2121307638 is about 46057.6555851468. The cubic root of 2121307638 is about 1284.8957281386.

The spelling of 2121307638 in words is "two billion, one hundred twenty-one million, three hundred seven thousand, six hundred thirty-eight".