21010030021 has 8 divisors (see below), whose sum is σ = 21329763840. Its totient is φ = 20692605168.

The previous prime is 21010030009. The next prime is 21010030031. The reversal of 21010030021 is 12003001012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21010030021 - 2²³ = 21001641413 is a prime.

It is a super-2 number, since 2×21010030021² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21010030001) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 558901 + ... + 595306.

It is an arithmetic number, because the mean of its divisors is an integer number (2666220480).

Almost surely, 2^21010030021 is an apocalyptic number.

It is an amenable number.

21010030021 is a deficient number, since it is larger than the sum of its proper divisors (319733819).

21010030021 is a wasteful number, since it uses less digits than its factorization.

21010030021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1154483.

The product of its (nonzero) digits is 12, while the sum is 10.

Adding to 21010030021 its reverse (12003001012), we get a palindrome (33013031033).

The spelling of 21010030021 in words is "twenty-one billion, ten million, thirty thousand, twenty-one".