21523154 has 8 divisors (see below), whose sum is σ = 32305548. Its totient is φ = 10754640.

The previous prime is 21523093. The next prime is 21523171. The reversal of 21523154 is 45132512.

It can be written as a sum of positive squares in 2 ways, for example, as 20839225 + 683929 = 4565^2 + 827^2 .

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

It is a Curzon number.

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, 2384 + ... + 6980.

Almost surely, 2^21523154 is an apocalyptic number.

21523154 is a deficient number, since it is larger than the sum of its proper divisors (10782394).

21523154 is a wasteful number, since it uses less digits than its factorization.

21523154 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6940.

The product of its digits is 1200, while the sum is 23.

The square root of 21523154 is about 4639.3053359312. The cubic root of 21523154 is about 278.1646713431.

Adding to 21523154 its reverse (45132512), we get a palindrome (66655666).

The spelling of 21523154 in words is "twenty-one million, five hundred twenty-three thousand, one hundred fifty-four".