121220021998 has 4 divisors (see below), whose sum is σ = 181830033000. Its totient is φ = 60610010998.

The previous prime is 121220021987. The next prime is 121220021999. The reversal of 121220021998 is 899120022121.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 899120022121 = 93739 ⋅9591739.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121220021999) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30305005498 + ... + 30305005501.

It is an arithmetic number, because the mean of its divisors is an integer number (45457508250).

Almost surely, 2^121220021998 is an apocalyptic number.

121220021998 is a deficient number, since it is larger than the sum of its proper divisors (60610011002).

121220021998 is an equidigital number, since it uses as much as digits as its factorization.

121220021998 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 60610011001.

The product of its (nonzero) digits is 10368, while the sum is 37.

The spelling of 121220021998 in words is "one hundred twenty-one billion, two hundred twenty million, twenty-one thousand, nine hundred ninety-eight".