21150745 has 32 divisors (see below), whose sum is σ = 31954176. Its totient is φ = 13056000.

The previous prime is 21150739. The next prime is 21150757. The reversal of 21150745 is 54705112.

It is not a de Polignac number, because 21150745 - 2²³ = 12762137 is a prime.

It is a Duffinian 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 31 ways as a sum of consecutive naturals, for example, 52545 + ... + 52945.

It is an arithmetic number, because the mean of its divisors is an integer number (998568).

Almost surely, 2^21150745 is an apocalyptic number.

It is an amenable number.

21150745 is a deficient number, since it is larger than the sum of its proper divisors (10803431).

21150745 is a wasteful number, since it uses less digits than its factorization.

21150745 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 561.

The product of its (nonzero) digits is 1400, while the sum is 25.

The square root of 21150745 is about 4598.9939117159. The cubic root of 21150745 is about 276.5509935630.

Adding to 21150745 its reverse (54705112), we get a palindrome (75855857).

The spelling of 21150745 in words is "twenty-one million, one hundred fifty thousand, seven hundred forty-five".