21121100010 has 24 divisors (see below), whose sum is σ = 54914860260. Its totient is φ = 5632293312.

The previous prime is 21121099991. The next prime is 21121100047. The reversal of 21121100010 is 1000112112.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 17893610289 + 3227489721 = 133767^2 + 56811^2 .

It is a super-2 number, since 2×21121100010² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a junction number, because it is equal to n+sod(n) for n = 21121099965 and 21121100001.

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 11 ways as a sum of consecutive naturals, for example, 117339355 + ... + 117339534.

Almost surely, 2^21121100010 is an apocalyptic number.

21121100010 is an abundant number, since it is smaller than the sum of its proper divisors (33793760250).

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

21121100010 is a wasteful number, since it uses less digits than its factorization.

21121100010 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 234678902 (or 234678899 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 9.

Adding to 21121100010 its reverse (1000112112), we get a palindrome (22121212122).

The spelling of 21121100010 in words is "twenty-one billion, one hundred twenty-one million, one hundred thousand, ten".