21149245 has 16 divisors (see below), whose sum is σ = 27441792. Its totient is φ = 15554880.

The previous prime is 21149243. The next prime is 21149251. The reversal of 21149245 is 54294112.

It is not a de Polignac number, because 21149245 - 2¹ = 21149243 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21149243) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 21024 + ... + 22006.

It is an arithmetic number, because the mean of its divisors is an integer number (1715112).

Almost surely, 2^21149245 is an apocalyptic number.

It is an amenable number.

21149245 is a deficient number, since it is larger than the sum of its proper divisors (6292547).

21149245 is a wasteful number, since it uses less digits than its factorization.

21149245 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1332.

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

The square root of 21149245 is about 4598.8308296783. The cubic root of 21149245 is about 276.5444557902.

The spelling of 21149245 in words is "twenty-one million, one hundred forty-nine thousand, two hundred forty-five".