21138101010 has 384 divisors, whose sum is σ = 65515806720. Its totient is φ = 4863234816.

The previous prime is 21138101003. The next prime is 21138101051. The reversal of 21138101010 is 1010183112.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is an unprimeable number.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 34148481 + ... + 34149099.

It is an arithmetic number, because the mean of its divisors is an integer number (170614080).

Almost surely, 2^21138101010 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21138101010, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32757903360).

21138101010 is an abundant number, since it is smaller than the sum of its proper divisors (44377705710).

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

21138101010 is a wasteful number, since it uses less digits than its factorization.

21138101010 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 724 (or 712 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 18.

Adding to 21138101010 its reverse (1010183112), we get a palindrome (22148284122).

The spelling of 21138101010 in words is "twenty-one billion, one hundred thirty-eight million, one hundred one thousand, ten".