9978822121 has 4 divisors (see below), whose sum is σ = 9992253312. Its totient is φ = 9965390932.

The previous prime is 9978822109. The next prime is 9978822127. The reversal of 9978822121 is 1212288799.

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: 1212288799 = 25409 ⋅47711.

It is a cyclic number.

It is not a de Polignac number, because 9978822121 - 2²¹ = 9976724969 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (9978822127) 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, 6714481 + ... + 6715966.

It is an arithmetic number, because the mean of its divisors is an integer number (2498063328).

Almost surely, 2^9978822121 is an apocalyptic number.

It is an amenable number.

9978822121 is a deficient number, since it is larger than the sum of its proper divisors (13431191).

9978822121 is a wasteful number, since it uses less digits than its factorization.

9978822121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13431190.

The product of its digits is 290304, while the sum is 49.

The square root of 9978822121 is about 99894.0544827369. The cubic root of 9978822121 is about 2152.9127365615.

The spelling of 9978822121 in words is "nine billion, nine hundred seventy-eight million, eight hundred twenty-two thousand, one hundred twenty-one".