21157242154 has 8 divisors (see below), whose sum is σ = 32043978720. Its totient is φ = 10475915916.

The previous prime is 21157242143. The next prime is 21157242157. The reversal of 21157242154 is 45124275112.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not an unprimeable number, because it can be changed into a prime (21157242157) by changing a digit.

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 in 3 ways as a sum of consecutive naturals, for example, 51352324 + ... + 51352735.

It is an arithmetic number, because the mean of its divisors is an integer number (4005497340).

Almost surely, 2^21157242154 is an apocalyptic number.

21157242154 is a deficient number, since it is larger than the sum of its proper divisors (10886736566).

21157242154 is a wasteful number, since it uses less digits than its factorization.

21157242154 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 102705164.

The product of its digits is 22400, while the sum is 34.

The spelling of 21157242154 in words is "twenty-one billion, one hundred fifty-seven million, two hundred forty-two thousand, one hundred fifty-four".