21221201220210 has 96 divisors (see below), whose sum is σ = 58631624945712. Its totient is φ = 5306877480960.

The previous prime is 21221201220209. The next prime is 21221201220229. The reversal of 21221201220210 is 1202210212212.

It is a happy number.

21221201220210 is a `hidden beast` number, since 2 + 1 + 221 + 201 + 220 + 21 + 0 = 666.

It can be written as a sum of positive squares in 8 ways, for example, as 12832722833841 + 8388478386369 = 3582279^2 + 2896287^2 .

It is a Harshad number since it is a multiple of its sum of digits (18).

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 24612411 + ... + 25460030.

Almost surely, 2^{21221201220210} is an apocalyptic number.

21221201220210 is an abundant number, since it is smaller than the sum of its proper divisors (37410423725502).

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

21221201220210 is a wasteful number, since it uses less digits than its factorization.

21221201220210 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50072748 (or 50072745 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 18.

Adding to 21221201220210 its reverse (1202210212212), we get a palindrome (22423411432422).

The spelling of 21221201220210 in words is "twenty-one trillion, two hundred twenty-one billion, two hundred one million, two hundred twenty thousand, two hundred ten".