102110100021 has 12 divisors (see below), whose sum is σ = 151478647372. Its totient is φ = 66233578176.

The previous prime is 102110100013. The next prime is 102110100047. The reversal of 102110100021 is 120001011201.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 55337387121 + 46772712900 = 235239^2 + 216270^2 .

It is not a de Polignac number, because 102110100021 - 2³ = 102110100013 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 102110099976 and 102110100012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (102110170021) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 153318136 + ... + 153318801.

Almost surely, 2^102110100021 is an apocalyptic number.

It is an amenable number.

102110100021 is a deficient number, since it is larger than the sum of its proper divisors (49368547351).

102110100021 is a wasteful number, since it uses less digits than its factorization.

102110100021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 306636980 (or 306636977 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 9.

Adding to 102110100021 its reverse (120001011201), we get a palindrome (222111111222).

The spelling of 102110100021 in words is "one hundred two billion, one hundred ten million, one hundred thousand, twenty-one".