21421102020 has 48 divisors (see below), whose sum is σ = 60191073600. Its totient is φ = 5692104576.

The previous prime is 21421101997. The next prime is 21421102067. The reversal of 21421102020 is 2020112412.

It is a super-2 number, since 2×21421102020² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (15).

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 15 ways as a sum of consecutive naturals, for example, 613795 + ... + 647754.

It is an arithmetic number, because the mean of its divisors is an integer number (1253980700).

Almost surely, 2^21421102020 is an apocalyptic number.

21421102020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21421102020 is an abundant number, since it is smaller than the sum of its proper divisors (38769971580).

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

21421102020 is a wasteful number, since it uses less digits than its factorization.

21421102020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1261844 (or 1261842 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 15.

Adding to 21421102020 its reverse (2020112412), we get a palindrome (23441214432).

The spelling of 21421102020 in words is "twenty-one billion, four hundred twenty-one million, one hundred two thousand, twenty".