21154249 has 4 divisors (see below), whose sum is σ = 21168400. Its totient is φ = 21140100.

The previous prime is 21154207. The next prime is 21154283. The reversal of 21154249 is 94245112.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21154249 - 2¹³ = 21146057 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21154849) by changing a digit.

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, 4527 + ... + 7924.

It is an arithmetic number, because the mean of its divisors is an integer number (5292100).

Almost surely, 2^21154249 is an apocalyptic number.

It is an amenable number.

21154249 is a deficient number, since it is larger than the sum of its proper divisors (14151).

21154249 is a wasteful number, since it uses less digits than its factorization.

21154249 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14150.

The product of its digits is 2880, while the sum is 28.

The square root of 21154249 is about 4599.3748488246. The cubic root of 21154249 is about 276.5662645960.

The spelling of 21154249 in words is "twenty-one million, one hundred fifty-four thousand, two hundred forty-nine".