20121232154 has 4 divisors (see below), whose sum is σ = 30181848234. Its totient is φ = 10060616076.

The previous prime is 20121232129. The next prime is 20121232259. The reversal of 20121232154 is 45123212102.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 45123212102 = 2 ⋅22561606051.

It can be written as a sum of positive squares in only one way, i.e., 13081183129 + 7040049025 = 114373^2 + 83905^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5030308037 + ... + 5030308040.

Almost surely, 2^20121232154 is an apocalyptic number.

20121232154 is a deficient number, since it is larger than the sum of its proper divisors (10060616080).

20121232154 is a wasteful number, since it uses less digits than its factorization.

20121232154 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10060616079.

The product of its (nonzero) digits is 960, while the sum is 23.

Adding to 20121232154 its reverse (45123212102), we get a palindrome (65244444256).

The spelling of 20121232154 in words is "twenty billion, one hundred twenty-one million, two hundred thirty-two thousand, one hundred fifty-four".