21011121010 has 32 divisors (see below), whose sum is σ = 41265303552. Its totient is φ = 7639092480.

The previous prime is 21011120993. The next prime is 21011121011. The reversal of 21011121010 is 1012111012.

It is a Harshad number since it is a multiple of its sum of digits (10).

It is not an unprimeable number, because it can be changed into a prime (21011121011) 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, 816399 + ... + 841741.

It is an arithmetic number, because the mean of its divisors is an integer number (1289540736).

Almost surely, 2^21011121010 is an apocalyptic number.

21011121010 is a deficient number, since it is larger than the sum of its proper divisors (20254182542).

21011121010 is a wasteful number, since it uses less digits than its factorization.

21011121010 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32898.

The product of its (nonzero) digits is 4, while the sum is 10.

Adding to 21011121010 its reverse (1012111012), we get a palindrome (22023232022).

The spelling of 21011121010 in words is "twenty-one billion, eleven million, one hundred twenty-one thousand, ten".