21001221210102 has 64 divisors (see below), whose sum is σ = 49407107549184. Its totient is φ = 5825512967040.

The previous prime is 21001221210023. The next prime is 21001221210107. The reversal of 21001221210102 is 20101212210012.

It is a super-2 number, since 2×21001221210102² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21001221210107) 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, 13941198 + ... + 15373985.

It is an arithmetic number, because the mean of its divisors is an integer number (771986055456).

Almost surely, 2^{21001221210102} is an apocalyptic number.

21001221210102 is an abundant number, since it is smaller than the sum of its proper divisors (28405886339082).

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

21001221210102 is a wasteful number, since it uses less digits than its factorization.

21001221210102 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29315693.

The product of its (nonzero) digits is 32, while the sum is 15.

Adding to 21001221210102 its reverse (20101212210012), we get a palindrome (41102433420114).

The spelling of 21001221210102 in words is "twenty-one trillion, one billion, two hundred twenty-one million, two hundred ten thousand, one hundred two".