21310445 has 8 divisors (see below), whose sum is σ = 27539736. Its totient is φ = 15736896.

The previous prime is 21310439. The next prime is 21310451. The reversal of 21310445 is 54401312.

It is an interprime number because it is at equal distance from previous prime (21310439) and next prime (21310451).

It can be written as a sum of positive squares in 4 ways, for example, as 1042441 + 20268004 = 1021^2 + 4502^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21310445 - 2⁸ = 21310189 is a prime.

It is a Duffinian number.

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 7 ways as a sum of consecutive naturals, for example, 163862 + ... + 163991.

It is an arithmetic number, because the mean of its divisors is an integer number (3442467).

Almost surely, 2^21310445 is an apocalyptic number.

It is an amenable number.

21310445 is a deficient number, since it is larger than the sum of its proper divisors (6229291).

21310445 is a wasteful number, since it uses less digits than its factorization.

21310445 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 327871.

The product of its (nonzero) digits is 480, while the sum is 20.

The square root of 21310445 is about 4616.3237538110. The cubic root of 21310445 is about 277.2452874721.

Adding to 21310445 its reverse (54401312), we get a palindrome (75711757).

The spelling of 21310445 in words is "twenty-one million, three hundred ten thousand, four hundred forty-five".