20100121210 has 32 divisors (see below), whose sum is σ = 39698482320. Its totient is φ = 7281550848.

The previous prime is 20100121187. The next prime is 20100121211. The reversal of 20100121210 is 1212100102.

It can be written as a sum of positive squares in 8 ways, for example, as 14653828809 + 5446292401 = 121053^2 + 73799^2 .

It is a Harshad number since it is a multiple of its sum of digits (10).

It is not an unprimeable number, because it can be changed into a prime (20100121211) by changing a digit.

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, 1451755 + ... + 1465534.

Almost surely, 2^20100121210 is an apocalyptic number.

20100121210 is a deficient number, since it is larger than the sum of its proper divisors (19598361110).

20100121210 is a wasteful number, since it uses less digits than its factorization.

20100121210 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2917362.

The product of its (nonzero) digits is 8, while the sum is 10.

Adding to 20100121210 its reverse (1212100102), we get a palindrome (21312221312).

The spelling of 20100121210 in words is "twenty billion, one hundred million, one hundred twenty-one thousand, two hundred ten".