21021020006 has 32 divisors (see below), whose sum is σ = 38034543360. Its totient is φ = 8511928416.

The previous prime is 21021019997. The next prime is 21021020057. The reversal of 21021020006 is 60002012012.

It is a Harshad number since it is a multiple of its sum of digits (14).

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6716 + ... + 205151.

It is an arithmetic number, because the mean of its divisors is an integer number (1188579480).

Almost surely, 2^21021020006 is an apocalyptic number.

21021020006 is a deficient number, since it is larger than the sum of its proper divisors (17013523354).

21021020006 is a wasteful number, since it uses less digits than its factorization.

21021020006 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 212268.

The product of its (nonzero) digits is 48, while the sum is 14.

Adding to 21021020006 its reverse (60002012012), we get a palindrome (81023032018).

The spelling of 21021020006 in words is "twenty-one billion, twenty-one million, twenty thousand, six".