21010030020 has 96 divisors (see below), whose sum is σ = 74702342400. Its totient is φ = 4802291712.

The previous prime is 21010030009. The next prime is 21010030031. The reversal of 21010030020 is 2003001012.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21010030009) and next prime (21010030031).

It is a super-2 number, since 2×21010030020² (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 = 21010029984 and 21010030011.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2775325 + ... + 2782884.

It is an arithmetic number, because the mean of its divisors is an integer number (778149400).

Almost surely, 2^21010030020 is an apocalyptic number.

21010030020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21010030020 is an abundant number, since it is smaller than the sum of its proper divisors (53692312380).

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

21010030020 is a wasteful number, since it uses less digits than its factorization.

21010030020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5558234 (or 5558226 counting only the distinct ones).

The product of its (nonzero) digits is 12, while the sum is 9.

Adding to 21010030020 its reverse (2003001012), we get a palindrome (23013031032).

The spelling of 21010030020 in words is "twenty-one billion, ten million, thirty thousand, twenty".