21299445 has 12 divisors (see below), whose sum is σ = 36919116. Its totient is φ = 11359680.

The previous prime is 21299423. The next prime is 21299461. The reversal of 21299445 is 54499212.

It can be written as a sum of positive squares in 2 ways, for example, as 15350724 + 5948721 = 3918^2 + 2439^2 .

It is not a de Polignac number, because 21299445 - 2⁶ = 21299381 is a prime.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 236616 + ... + 236705.

It is an arithmetic number, because the mean of its divisors is an integer number (3076593).

Almost surely, 2^21299445 is an apocalyptic number.

It is an amenable number.

21299445 is a deficient number, since it is larger than the sum of its proper divisors (15619671).

21299445 is a wasteful number, since it uses less digits than its factorization.

21299445 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 473332 (or 473329 counting only the distinct ones).

The product of its digits is 25920, while the sum is 36.

The square root of 21299445 is about 4615.1321757887. The cubic root of 21299445 is about 277.1975765485.

The spelling of 21299445 in words is "twenty-one million, two hundred ninety-nine thousand, four hundred forty-five".