21340245 has 16 divisors (see below), whose sum is σ = 35246592. Its totient is φ = 11014080.

The previous prime is 21340243. The next prime is 21340247. The reversal of 21340245 is 54204312.

It is an interprime number because it is at equal distance from previous prime (21340243) and next prime (21340247).

It is not a de Polignac number, because 21340245 - 2¹ = 21340243 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21340243) 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, 22482 + ... + 23411.

It is an arithmetic number, because the mean of its divisors is an integer number (2202912).

Almost surely, 2^21340245 is an apocalyptic number.

It is an amenable number.

21340245 is a deficient number, since it is larger than the sum of its proper divisors (13906347).

21340245 is a wasteful number, since it uses less digits than its factorization.

21340245 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45932.

The product of its (nonzero) digits is 960, while the sum is 21.

The square root of 21340245 is about 4619.5503027892. The cubic root of 21340245 is about 277.3744582688.

Adding to 21340245 its reverse (54204312), we get a palindrome (75544557).

The spelling of 21340245 in words is "twenty-one million, three hundred forty thousand, two hundred forty-five".