21101145 has 16 divisors (see below), whose sum is σ = 36359232. Its totient is φ = 10388160.

The previous prime is 21101123. The next prime is 21101207. The reversal of 21101145 is 54110112.

It is a happy number.

It is not a de Polignac number, because 21101145 - 2¹¹ = 21099097 is a prime.

It is a super-2 number, since 2×21101145² = 890516640622050, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is an unprimeable number.

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, 53911 + ... + 54300.

It is an arithmetic number, because the mean of its divisors is an integer number (2272452).

Almost surely, 2^21101145 is an apocalyptic number.

It is an amenable number.

21101145 is a deficient number, since it is larger than the sum of its proper divisors (15258087).

21101145 is a wasteful number, since it uses less digits than its factorization.

21101145 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 108232.

The product of its (nonzero) digits is 40, while the sum is 15.

The square root of 21101145 is about 4593.5982628001. The cubic root of 21101145 is about 276.3346471150.

Adding to 21101145 its reverse (54110112), we get a palindrome (75211257).

The spelling of 21101145 in words is "twenty-one million, one hundred one thousand, one hundred forty-five".