102001100021 has 4 divisors (see below), whose sum is σ = 103925649132. Its totient is φ = 100076550912.

The previous prime is 102001100011. The next prime is 102001100023. The reversal of 102001100021 is 120001100201.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 60558319396 + 41442780625 = 246086^2 + 203575^2 .

It is a cyclic number.

It is not a de Polignac number, because 102001100021 - 2¹⁸ = 102000837877 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 102001099981 and 102001100008.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (102001100023) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 962274476 + ... + 962274581.

It is an arithmetic number, because the mean of its divisors is an integer number (25981412283).

Almost surely, 2^102001100021 is an apocalyptic number.

It is an amenable number.

102001100021 is a deficient number, since it is larger than the sum of its proper divisors (1924549111).

102001100021 is an equidigital number, since it uses as much as digits as its factorization.

102001100021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1924549110.

The product of its (nonzero) digits is 4, while the sum is 8.

Adding to 102001100021 its reverse (120001100201), we get a palindrome (222002200222).

The spelling of 102001100021 in words is "one hundred two billion, one million, one hundred thousand, twenty-one".