21288045 has 16 divisors (see below), whose sum is σ = 34212672. Its totient is φ = 11303040.

The previous prime is 21288031. The next prime is 21288049. The reversal of 21288045 is 54088212.

It is not a de Polignac number, because 21288045 - 2⁵ = 21288013 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21288049) 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, 450 + ... + 6540.

It is an arithmetic number, because the mean of its divisors is an integer number (2138292).

Almost surely, 2^21288045 is an apocalyptic number.

It is an amenable number.

21288045 is a deficient number, since it is larger than the sum of its proper divisors (12924627).

21288045 is a wasteful number, since it uses less digits than its factorization.

21288045 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6332.

The product of its (nonzero) digits is 5120, while the sum is 30.

The square root of 21288045 is about 4613.8969429323. The cubic root of 21288045 is about 277.1481133454.

The spelling of 21288045 in words is "twenty-one million, two hundred eighty-eight thousand, forty-five".