102121100021 has 4 divisors (see below), whose sum is σ = 106561147872. Its totient is φ = 97681052172.

The previous prime is 102121100009. The next prime is 102121100033. The reversal of 102121100021 is 120001121201.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 120001121201 = 13 ⋅9230855477.

It is an interprime number because it is at equal distance from previous prime (102121100009) and next prime (102121100033).

It is a cyclic number.

It is not a de Polignac number, because 102121100021 - 2³⁴ = 84941230837 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 102121099975 and 102121100011.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (102121100051) 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, 2220023891 + ... + 2220023936.

It is an arithmetic number, because the mean of its divisors is an integer number (26640286968).

Almost surely, 2^102121100021 is an apocalyptic number.

It is an amenable number.

102121100021 is a deficient number, since it is larger than the sum of its proper divisors (4440047851).

102121100021 is an equidigital number, since it uses as much as digits as its factorization.

102121100021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4440047850.

The product of its (nonzero) digits is 8, while the sum is 11.

Adding to 102121100021 its reverse (120001121201), we get a palindrome (222122221222).

The spelling of 102121100021 in words is "one hundred two billion, one hundred twenty-one million, one hundred thousand, twenty-one".