21000421011 has 16 divisors (see below), whose sum is σ = 29713716000. Its totient is φ = 13147373568.

The previous prime is 21000421003. The next prime is 21000421033. The reversal of 21000421011 is 11012400012.

It is a happy number.

It is not a de Polignac number, because 21000421011 - 2³ = 21000421003 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21000421411) 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, 435646 + ... + 481443.

It is an arithmetic number, because the mean of its divisors is an integer number (1857107250).

Almost surely, 2^21000421011 is an apocalyptic number.

21000421011 is a deficient number, since it is larger than the sum of its proper divisors (8713294989).

21000421011 is a wasteful number, since it uses less digits than its factorization.

21000421011 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 917558.

The product of its (nonzero) digits is 16, while the sum is 12.

Adding to 21000421011 its reverse (11012400012), we get a palindrome (32012821023).

The spelling of 21000421011 in words is "twenty-one billion, four hundred twenty-one thousand, eleven".