21221000210 has 16 divisors (see below), whose sum is σ = 40444730136. Its totient is φ = 7989082368.

The previous prime is 21221000201. The next prime is 21221000233. The reversal of 21221000210 is 1200012212.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 13414040761 + 7806959449 = 115819^2 + 88357^2 .

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21221000191 and 21221000200.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 62414537 + ... + 62414876.

Almost surely, 2^21221000210 is an apocalyptic number.

21221000210 is a deficient number, since it is larger than the sum of its proper divisors (19223729926).

21221000210 is a wasteful number, since it uses less digits than its factorization.

21221000210 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 124829437.

The product of its (nonzero) digits is 16, while the sum is 11.

Adding to 21221000210 its reverse (1200012212), we get a palindrome (22421012422).

The spelling of 21221000210 in words is "twenty-one billion, two hundred twenty-one million, two hundred ten", and thus it is an aban number.