21541636154 has 4 divisors (see below), whose sum is σ = 32312454234. Its totient is φ = 10770818076.

The previous prime is 21541636141. The next prime is 21541636163. The reversal of 21541636154 is 45163614512.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 16546963225 + 4994672929 = 128635^2 + 70673^2 .

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, 5385409037 + ... + 5385409040.

Almost surely, 2^21541636154 is an apocalyptic number.

21541636154 is a deficient number, since it is larger than the sum of its proper divisors (10770818080).

21541636154 is a wasteful number, since it uses less digits than its factorization.

21541636154 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10770818079.

The product of its digits is 86400, while the sum is 38.

The spelling of 21541636154 in words is "twenty-one billion, five hundred forty-one million, six hundred thirty-six thousand, one hundred fifty-four".