21007700838 has 32 divisors (see below), whose sum is σ = 47146007520. Its totient is φ = 6933232800.

The previous prime is 21007700837. The next prime is 21007700849. The reversal of 21007700838 is 83800770012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21007700837) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1920445 + ... + 1931352.

It is an arithmetic number, because the mean of its divisors is an integer number (1473312735).

Almost surely, 2^21007700838 is an apocalyptic number.

21007700838 is an abundant number, since it is smaller than the sum of its proper divisors (26138306682).

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

21007700838 is a wasteful number, since it uses less digits than its factorization.

21007700838 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3851909 (or 3851903 counting only the distinct ones).

The product of its (nonzero) digits is 18816, while the sum is 36.

The spelling of 21007700838 in words is "twenty-one billion, seven million, seven hundred thousand, eight hundred thirty-eight".