21309154 has 8 divisors (see below), whose sum is σ = 32293548. Its totient is φ = 10544640.

The previous prime is 21309133. The next prime is 21309179. The reversal of 21309154 is 45190312.

It can be written as a sum of positive squares in 2 ways, for example, as 20043529 + 1265625 = 4477^2 + 1125^2 .

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, 54727 + ... + 55114.

Almost surely, 2^21309154 is an apocalyptic number.

21309154 is a deficient number, since it is larger than the sum of its proper divisors (10984394).

21309154 is a wasteful number, since it uses less digits than its factorization.

21309154 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 109940.

The product of its (nonzero) digits is 1080, while the sum is 25.

The square root of 21309154 is about 4616.1839218125. The cubic root of 21309154 is about 277.2396887951.

Adding to 21309154 its reverse (45190312), we get a palindrome (66499466).

The spelling of 21309154 in words is "twenty-one million, three hundred nine thousand, one hundred fifty-four".