21045311 has 16 divisors (see below), whose sum is σ = 24987648. Its totient is φ = 17344800.

The previous prime is 21045301. The next prime is 21045317. The reversal of 21045311 is 11354012.

It is a cyclic number.

It is not a de Polignac number, because 21045311 - 2¹⁸ = 20783167 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21045311.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21045317) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 63416 + ... + 63746.

It is an arithmetic number, because the mean of its divisors is an integer number (1561728).

Almost surely, 2^21045311 is an apocalyptic number.

21045311 is a deficient number, since it is larger than the sum of its proper divisors (3942337).

21045311 is a wasteful number, since it uses less digits than its factorization.

21045311 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 662.

The product of its (nonzero) digits is 120, while the sum is 17.

The square root of 21045311 is about 4587.5168664540. The cubic root of 21045311 is about 276.0907030528.

Adding to 21045311 its reverse (11354012), we get a palindrome (32399323).

The spelling of 21045311 in words is "twenty-one million, forty-five thousand, three hundred eleven".