21201021022220 has 96 divisors (see below), whose sum is σ = 51090692260608. Its totient is φ = 7320667041792.

The previous prime is 21201021022213. The next prime is 21201021022229. The reversal of 21201021022220 is 2222012010212.

It is a happy number.

It is a super-2 number, since 2×21201021022220² (a number of 27 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (17).

It is not an unprimeable number, because it can be changed into a prime (21201021022229) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 14581892 + ... + 15969771.

It is an arithmetic number, because the mean of its divisors is an integer number (532194711048).

Almost surely, 2^{21201021022220} is an apocalyptic number.

21201021022220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21201021022220 is an abundant number, since it is smaller than the sum of its proper divisors (29889671238388).

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

21201021022220 is a wasteful number, since it uses less digits than its factorization.

21201021022220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30551859 (or 30551857 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 17.

Adding to 21201021022220 its reverse (2222012010212), we get a palindrome (23423033032432).

The spelling of 21201021022220 in words is "twenty-one trillion, two hundred one billion, twenty-one million, twenty-two thousand, two hundred twenty".