21645154 has 8 divisors (see below), whose sum is σ = 32952528. Its totient is φ = 10660980.

The previous prime is 21645133. The next prime is 21645167. The reversal of 21645154 is 45154612.

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 80632 + ... + 80899.

It is an arithmetic number, because the mean of its divisors is an integer number (4119066).

Almost surely, 2^21645154 is an apocalyptic number.

21645154 is a deficient number, since it is larger than the sum of its proper divisors (11307374).

21645154 is a wasteful number, since it uses less digits than its factorization.

21645154 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 161600.

The product of its digits is 4800, while the sum is 28.

The square root of 21645154 is about 4652.4352762827. The cubic root of 21645154 is about 278.6892563385.

Adding to 21645154 its reverse (45154612), we get a palindrome (66799766).

The spelling of 21645154 in words is "twenty-one million, six hundred forty-five thousand, one hundred fifty-four".